| Transactions |
| Date | Team | Player | Type | OthTm | EffDate | When |
| 4/8/2012 | CLE | Carter | Promoted to active roster | | | Before |
| 4/8/2012 | CLE | Cooper | Demoted to reserve roster | | | Before |
| 4/8/2012 | CLE | Hochevar | Promoted to active roster | | | Before |
| 4/8/2012 | CLE | Mayberry | Promoted to active roster | | | Before |
| 4/8/2012 | DUR | Atchison | Placed on disabled list | | 4/6/2012 | Before |
| 4/8/2012 | DUR | Lyles | Demoted to reserve roster | | | Before |
| 4/8/2012 | DUR | Nava | Demoted to reserve roster | | | Before |
| 4/8/2012 | DUR | Perez,O | Promoted to active roster | | | Before |
| 4/8/2012 | MAN | Cecil | Placed on disabled list | | 4/6/2012 | Before |
| 4/8/2012 | MAN | Collmenter | Promoted to active roster | | | Before |
| 4/8/2012 | MAN | Wells,R | Promoted to active roster | | | Before |
| 4/8/2012 | MAN | Zito | Placed on disabled list | | 4/7/2012 | Before |
| 4/8/2012 | MON | Gonzalez,Ma | Promoted to active roster | | | Before |
| 4/8/2012 | MON | Kottaras,G | Demoted to reserve roster | | | Before |
| 4/8/2012 | MON | Martin | Promoted to active roster | | | Before |
| 4/8/2012 | MON | Rutledge | Demoted to reserve roster | | | Before |
| 4/11/2012 | AVA | Storey | Promoted to active roster | | | Before |
| 4/11/2012 | AVA | Uribe | Demoted to reserve roster | | | Before |
| 4/11/2012 | BOX | Brown,D | Promoted to active roster | | | Before |
| 4/11/2012 | BOX | Howard | Placed on disabled list | | 4/11/2012 | Before |
| 4/11/2012 | DSP | Morse | Placed on disabled list | | 4/9/2012 | Before |
| 4/11/2012 | DSP | Reimold | Promoted to active roster | | | Before |
| 4/14/2012 | ASB | Pettitte | Placed on disabled list | | 4/13/2012 | Before |
| 4/14/2012 | ASB | Pomeranz,D | Promoted to active roster | | | Before |
| 4/14/2012 | CGS | Boxberger | Promoted to active roster | | | Before |
| 4/14/2012 | CGS | Peavy | Placed on disabled list | | 4/13/2012 | Before |
| 4/14/2012 | MAN | Anderson,BF | Promoted to active roster | | | Before |
| 4/14/2012 | MAN | Wells,R | Demoted to reserve roster | | | Before |
| 4/14/2012 | PEA | Buchholz | Placed on disabled list | | 4/14/2012 | Before |
| 4/14/2012 | PEA | Swarzak | Promoted to active roster | | | Before |
| 4/14/2012 | TOR | Hughes,P | Placed on disabled list | | 4/13/2012 | Before |
| 4/14/2012 | TOR | Karstens | Promoted to active roster | | | Before |
| 4/17/2012 | AVA | Price | Placed on disabled list | | 4/16/2012 | Before |
| 4/17/2012 | AVA | Uribe | Promoted to active roster | | | Before |
| 4/17/2012 | NHP | Harvey | Promoted to active roster | | | Before |
| 4/17/2012 | NHP | Rodriguez,S | Demoted to reserve roster | | | Before |
| 4/20/2012 | HOL | Neshek | Promoted to active roster | | | Before |
| 4/20/2012 | HOL | Parker,J | Placed on disabled list | | 4/19/2012 | Before |
| 4/20/2012 | TOR | Kearns | Demoted to reserve roster | | | Before |
| 4/20/2012 | TOR | Schumaker | Promoted to active roster | | | Before |
| 4/23/2012 | HOL | Duffy | Promoted to active roster | | | Before |
| 4/23/2012 | HOL | Sabathia | Placed on disabled list | | 4/21/2012 | Before |
| 4/23/2012 | MAN | Anderson,BF | Demoted to reserve roster | | | Before |
| 4/23/2012 | MAN | Collmenter | Demoted to reserve roster | | | Before |
| 4/23/2012 | MAN | Guerra | Promoted to active roster | | | Before |
| 4/23/2012 | MAN | Ishikawa | Demoted to reserve roster | | | Before |
| 4/23/2012 | MAN | Rolen | Promoted to active roster | | | Before |
| 4/23/2012 | MAN | Zito | Activated from disabled list | | | Before |
| 4/23/2012 | NHP | Crisp | Placed on disabled list | | 4/18/2012 | Before |
| 4/23/2012 | NHP | Rodriguez,S | Promoted to active roster | | | Before |
| 4/23/2012 | PBC | Lyon,B | Promoted to active roster | | | Before |
| 4/23/2012 | PBC | Thayer | Demoted to reserve roster | | | Before |
| 4/26/2012 | ASB | Bedard | Promoted to active roster | | | Before |
| 4/26/2012 | ASB | Weaver | Placed on disabled list | | 4/26/2012 | Before |
| 4/26/2012 | AUR | Jackson,E | Placed on disabled list | | 4/24/2012 | Before |
| 4/26/2012 | AUR | Johnson,S | Promoted to active roster | | | Before |
| 4/26/2012 | BBK | Davis,R | Placed on disabled list | | 4/25/2012 | Before |
| 4/26/2012 | BBK | Eaton | Promoted to active roster | | | Before |
| 4/26/2012 | DUR | Atchison | Activated from disabled list | | | Before |
| 4/26/2012 | DUR | Walden | Demoted to reserve roster | | | Before |
| 4/26/2012 | PBC | Parra,G | Promoted to active roster | | | Before |
| 4/26/2012 | PBC | Rasmus | Demoted to reserve roster | | | Before |
| 4/26/2012 | WTB | Arias | Promoted to active roster | | | Before |
| 4/26/2012 | WTB | Willingham | Placed on disabled list | | 4/25/2012 | Before |
| 4/29/2012 | AVA | Capps,M | Promoted to active roster | | | Before |
| 4/29/2012 | AVA | Uribe | Demoted to reserve roster | | | Before |
| 4/29/2012 | CGS | Boxberger | Demoted to reserve roster | | | Before |
| 4/29/2012 | CGS | Peavy | Activated from disabled list | | | Before |
| 4/29/2012 | DSP | Flores | Placed on disabled list | | 4/29/2012 | Before |
| 4/29/2012 | DSP | Hayes | Promoted to active roster | | | Before |
| 4/29/2012 | DUR | De Vries | Promoted to active roster | | | Before |
| 4/29/2012 | DUR | Oliver | Demoted to reserve roster | | | Before |
| 4/29/2012 | MAN | Cecil | Activated from disabled list | | | Before |
| 4/29/2012 | MAN | Guerra | Demoted to reserve roster | | | Before |
| 4/29/2012 | MAN | Jimenez,L | Released | | | Before |
| 4/29/2012 | NHP | Garcia,A | Promoted to active roster | | | Before |
| 4/29/2012 | NHP | Harvey | Demoted to reserve roster | | | Before |
| 4/29/2012 | TOR | Hughes,P | Activated from disabled list | | | Before |
| 4/29/2012 | TOR | Karstens | Demoted to reserve roster | | | Before |
| 5/1/2012 | CGS | Blackley,T | Traded away | MAN | | After |
| 5/1/2012 | CGS | Bruce | Acquired via trade | MAN | | After |
| 5/1/2012 | CGS | Castillo | Traded away | MAN | | After |
| 5/1/2012 | CGS | Friedrich | Traded away | MAN | | After |
| 5/1/2012 | CGS | Jimenez,U | Traded away | MAN | | After |
| 5/1/2012 | CGS | Johnson,Ro | Acquired via trade | MAN | | After |
| 5/1/2012 | CGS | Loney,J | Traded away | MAN | | After |
| 5/1/2012 | CGS | Morrison | Traded away | MAN | | After |
| 5/1/2012 | CGS | Rolen | Acquired via trade | MAN | | After |
| 5/1/2012 | CGS | Thome,J | Acquired via trade | MAN | | After |
| 5/1/2012 | CGS | Vitters | Traded away | MAN | | After |
| 5/1/2012 | CGS | Williams | Acquired via trade | MAN | | After |
| 5/1/2012 | CLE | Cooper | Traded away | MAN | | After |
| 5/1/2012 | CLE | Escalona | Acquired via trade | MAN | | After |
| 5/1/2012 | DEG | Lincoln,B | Traded away | DUR | | After |
| 5/1/2012 | DEG | Lyles | Acquired via trade | DUR | | After |
| 5/1/2012 | DEG | Smith,W | Traded away | DUR | | After |
| 5/1/2012 | DUR | Allen,C | Acquired via trade | MAN | | After |
| 5/1/2012 | DUR | Chatwood | Traded away | MAN | | After |
| 5/1/2012 | DUR | Hafner | Traded away | MAN | | After |
| 5/1/2012 | DUR | Hill,R | Acquired via trade | MAN | | After |
| 5/1/2012 | DUR | Lincoln,B | Acquired via trade | DEG | | After |
| 5/1/2012 | DUR | Lyles | Traded away | DEG | | After |
| 5/1/2012 | DUR | Smith,W | Acquired via trade | DEG | | After |
| 5/1/2012 | MAN | Allen,C | Traded away | DUR | | After |
| 5/1/2012 | MAN | Blackley,T | Acquired via trade | CGS | | After |
| 5/1/2012 | MAN | Bruce | Traded away | CGS | | After |
| 5/1/2012 | MAN | Castillo | Acquired via trade | CGS | | After |
| 5/1/2012 | MAN | Chatwood | Acquired via trade | DUR | | After |
| 5/1/2012 | MAN | Cooper | Acquired via trade | CLE | | After |
| 5/1/2012 | MAN | Escalona | Traded away | CLE | | After |
| 5/1/2012 | MAN | Friedrich | Acquired via trade | CGS | | After |
| 5/1/2012 | MAN | Hafner | Acquired via trade | DUR | | After |
| 5/1/2012 | MAN | Hill,R | Traded away | DUR | | After |
| 5/1/2012 | MAN | Jimenez,U | Acquired via trade | CGS | | After |
| 5/1/2012 | MAN | Johnson,Ro | Traded away | CGS | | After |
| 5/1/2012 | MAN | Loney,J | Acquired via trade | CGS | | After |
| 5/1/2012 | MAN | Morrison | Acquired via trade | CGS | | After |
| 5/1/2012 | MAN | Rolen | Traded away | CGS | | After |
| 5/1/2012 | MAN | Thome,J | Traded away | CGS | | After |
| 5/1/2012 | MAN | Vitters | Acquired via trade | CGS | | After |
| 5/1/2012 | MAN | Williams | Traded away | CGS | | After |
| 5/2/2012 | ASB | Bedard | Demoted to reserve roster | | | Before |
| 5/2/2012 | ASB | Pettitte | Activated from disabled list | | | Before |
| 5/2/2012 | AUR | Francis | Promoted to active roster | | | Before |
| 5/2/2012 | AUR | Johnson,S | Placed on disabled list | | 4/29/2012 | Before |
| 5/2/2012 | AVA | Price | Activated from disabled list | | | Before |
| 5/2/2012 | AVA | Storey | Demoted to reserve roster | | | Before |
| 5/2/2012 | CGS | Blackley,T | Demoted to reserve roster | | | Before |
| 5/2/2012 | CGS | Castillo | Demoted to reserve roster | | | Before |
| 5/2/2012 | CGS | Chisenhall | Promoted to active roster | | | Before |
| 5/2/2012 | CGS | Johnson,Ro | Demoted to reserve roster | | | Before |
| 5/2/2012 | CGS | Reynolds,MA | Demoted to reserve roster | | | Before |
| 5/2/2012 | CGS | Rolen | Demoted to reserve roster | | | Before |
| 5/2/2012 | CGS | Thome,J | Demoted to reserve roster | | | Before |
| 5/2/2012 | DUR | Oliver | Promoted to active roster | | | Before |
| 5/2/2012 | DUR | Perez,O | Demoted to reserve roster | | | Before |
| 5/2/2012 | MAN | Cooper | Promoted to active roster | | | Before |
| 5/2/2012 | MAN | Hafner | Promoted to active roster | | | Before |
| 5/2/2012 | MAN | Herrera | Promoted to active roster | | | Before |
| 5/2/2012 | MAN | Pelfrey | Promoted to active roster | | | Before |
| 5/2/2012 | MAN | Pryor | Promoted to active roster | | | Before |
| 5/2/2012 | TOR | Karstens | Promoted to active roster | | | Before |
| 5/2/2012 | TOR | Tillman | Placed on disabled list | | 5/2/2012 | Before |
| 5/4/2012 | CLE | Gomez,M | Traded away | DUR | | After |
| 5/4/2012 | DUR | Gomez,M | Acquired via trade | CLE | | After |
| 5/5/2012 | AUR | Buck,J | Placed on disabled list | | 5/3/2012 | Before |
| 5/5/2012 | AUR | Mathis | Promoted to active roster | | | Before |
| 5/5/2012 | BOX | Brown,D | Demoted to reserve roster | | | Before |
| 5/5/2012 | BOX | Segura,J | Promoted to active roster | | | Before |
| 5/5/2012 | CGS | Chisenhall | Promoted to active roster | | | Before |
| 5/5/2012 | CGS | Escobar,E | Promoted to active roster | | | Before |
| 5/5/2012 | CGS | Reynolds,MA | Demoted to reserve roster | | | Before |
| 5/5/2012 | CGS | Walker | Placed on disabled list | | 5/3/2012 | Before |
| 5/5/2012 | DEG | Keuchel | Promoted to active roster | | | Before |
| 5/5/2012 | DEG | Peralta,W | Promoted to active roster | | | Before |
| 5/5/2012 | DEG | Robinson,T | Demoted to reserve roster | | | Before |
| 5/5/2012 | DEG | Santana,E | Placed on disabled list | | 5/5/2012 | Before |
| 5/5/2012 | DUR | De Vries | Demoted to reserve roster | | | Before |
| 5/5/2012 | DUR | Hill,R | Demoted to reserve roster | | | Before |
| 5/5/2012 | HOL | Parker,J | Activated from disabled list | | | Before |
| 5/5/2012 | HOL | Rivera,M | Demoted to reserve roster | | | Before |
| 5/5/2012 | MAN | Collmenter | Promoted to active roster | | | Before |
| 5/5/2012 | MON | Doubront | Promoted to active roster | | | Before |
| 5/5/2012 | MON | Fiers | Placed on disabled list | | 5/3/2012 | Before |
| 5/5/2012 | NHP | Crisp | Activated from disabled list | | | Before |
| 5/5/2012 | NHP | Garcia,A | Demoted to reserve roster | | | Before |
| 5/5/2012 | PEA | Buchholz | Activated from disabled list | | | Before |
| 5/5/2012 | PEA | Haren | Placed on disabled list | | 5/5/2012 | Before |
| 5/5/2012 | TOR | Kearns | Promoted to active roster | | | Before |
| 5/5/2012 | TOR | Schumaker | Demoted to reserve roster | | | Before |
| 5/8/2012 | ASB | Bedard | Promoted to active roster | | | Before |
| 5/8/2012 | ASB | Smyly | Placed on disabled list | | 5/5/2012 | Before |
| 5/8/2012 | DEG | Floyd | Placed on disabled list | | 5/7/2012 | Before |
| 5/8/2012 | DEG | Lyles | Promoted to active roster | | | Before |
| 5/8/2012 | DUR | Lewis,C | Demoted to reserve roster | | | Before |
| 5/8/2012 | DUR | Smith,W | Promoted to active roster | | | Before |
| 5/8/2012 | HOL | Neshek | Demoted to reserve roster | | | Before |
| 5/8/2012 | HOL | Sabathia | Activated from disabled list | | | Before |
| 5/8/2012 | MAN | Anderson,BF | Promoted to active roster | | | Before |
| 5/8/2012 | MAN | Pelfrey | Demoted to reserve roster | | | Before |
| 5/8/2012 | PBC | Rodriguez,Al | Placed on disabled list | | 5/8/2012 | Before |
| 5/8/2012 | PBC | Young,D | Promoted to active roster | | | Before |
| 5/10/2012 | CLE | Danks,JW | Traded away | MAN | | After |
| 5/10/2012 | CLE | Hoover | Traded away | MAN | | After |
| 5/10/2012 | CLE | Hosmer | Acquired via trade | MAN | | After |
| 5/10/2012 | CLE | Stults,E | Traded away | MAN | | After |
| 5/10/2012 | DSP | Lough | Traded away | MAN | | After |
| 5/10/2012 | DSP | Pearce,S | Acquired via trade | MAN | | After |
| 5/10/2012 | MAN | Danks,JW | Acquired via trade | CLE | | After |
| 5/10/2012 | MAN | Hoover | Acquired via trade | CLE | | After |
| 5/10/2012 | MAN | Hosmer | Traded away | CLE | | After |
| 5/10/2012 | MAN | Hughes,J | Traded away | NHP | | After |
| 5/10/2012 | MAN | Lough | Acquired via trade | DSP | | After |
| 5/10/2012 | MAN | Pearce,S | Traded away | DSP | | After |
| 5/10/2012 | MAN | Stults,E | Acquired via trade | CLE | | After |
| 5/10/2012 | NHP | Hughes,J | Acquired via trade | MAN | | After |
| 5/11/2012 | BBK | Davis,R | Activated from disabled list | | | Before |
| 5/11/2012 | BBK | Eaton | Demoted to reserve roster | | | Before |
| 5/11/2012 | CLE | Blackburn | Promoted to active roster | | | Before |
| 5/11/2012 | CLE | Escalona | Promoted to active roster | | | Before |
| 5/11/2012 | CRB | Ramos,C | Promoted to active roster | | | Before |
| 5/11/2012 | CRB | Shaw | Demoted to reserve roster | | | Before |
| 5/11/2012 | DSP | Adams,Mi | Demoted to reserve roster | | | Before |
| 5/11/2012 | DSP | Rodriguez,H | Promoted to active roster | | | Before |
| 5/11/2012 | DUR | Gomez,M | Promoted to active roster | | | Before |
| 5/11/2012 | DUR | LaRoche | Placed on disabled list | | 5/11/2012 | Before |
| 5/11/2012 | DUR | Perez,O | Promoted to active roster | | | Before |
| 5/11/2012 | DUR | Smith,W | Demoted to reserve roster | | | Before |
| 5/11/2012 | MAN | Anderson,BF | Demoted to reserve roster | | | Before |
| 5/11/2012 | MAN | Hoover | Promoted to active roster | | | Before |
| 5/11/2012 | MAN | Ishikawa | Promoted to active roster | | | Before |
| 5/11/2012 | MAN | Pryor | Demoted to reserve roster | | | Before |
| 5/11/2012 | MAN | Stults,E | Demoted to reserve roster | | | Before |
| 5/11/2012 | NHP | Bass | Demoted to reserve roster | | | Before |
| 5/11/2012 | NHP | Gonzalez,Mig | Demoted to reserve roster | | | Before |
| 5/11/2012 | NHP | Gonzalez,Mig | Promoted to active roster | | | Before |
| 5/11/2012 | NHP | Harvey | Promoted to active roster | | | Before |
| 5/11/2012 | WCM | Bloomquist | Promoted to active roster | | | Before |
| 5/11/2012 | WCM | Markakis | Placed on disabled list | | 5/7/2012 | Before |
| 5/11/2012 | WTB | Arias | Demoted to reserve roster | | | Before |
| 5/11/2012 | WTB | Willingham | Activated from disabled list | | | Before |
| 5/14/2012 | CLE | Bauer | Promoted to active roster | | | Before |
| 5/14/2012 | CLE | Halladay | Placed on disabled list | | 5/12/2012 | Before |
| 5/14/2012 | CLE | Hutchison | Promoted to active roster | | | Before |
| 5/14/2012 | CLE | Lynn,L | Placed on disabled list | | 5/11/2012 | Before |
| 5/14/2012 | DSP | Venable | Placed on disabled list | | 5/9/2012 | Before |
| 5/14/2012 | DUR | Lewis,C | Demoted to reserve roster | | | Before |
| 5/14/2012 | DUR | Lewis,C | Promoted to active roster | | | Before |
| 5/14/2012 | DUR | Lincoln,B | Promoted to active roster | | | Before |
| 5/14/2012 | DUR | Wright,W | Demoted to reserve roster | | | Before |
| 5/14/2012 | HOL | Detwiler | Placed on disabled list | | 5/12/2012 | Before |
| 5/14/2012 | HOL | Layne | Promoted to active roster | | | Before |
| 5/14/2012 | MAN | Danks,JW | Demoted to reserve roster | | | Before |
| 5/14/2012 | MAN | Stults,E | Promoted to active roster | | | Before |
| 5/14/2012 | MON | Cobb | Placed on disabled list | | 5/10/2012 | Before |
| 5/14/2012 | MON | Delgado | Promoted to active roster | | | Before |
| 5/17/2012 | BOX | Feliz | Demoted to reserve roster | | | Before |
| 5/17/2012 | BOX | Paulino,F | Promoted to active roster | | | Before |
| 5/17/2012 | BOX | Volquez | Demoted to reserve roster | | | Before |
| 5/17/2012 | BOX | Zambrano | Promoted to active roster | | | Before |
| 5/17/2012 | DSP | Flores | Activated from disabled list | | | Before |
| 5/17/2012 | DSP | Ross,D | Demoted to reserve roster | | | Before |
| 5/17/2012 | DUR | Chavez,Er | Demoted to reserve roster | | | Before |
| 5/17/2012 | DUR | Crawford,B | Demoted to reserve roster | | | Before |
| 5/17/2012 | DUR | Gonzalez,Al | Promoted to active roster | | | Before |
| 5/17/2012 | DUR | Lewis,C | Promoted to active roster | | | Before |
| 5/17/2012 | DUR | Lincoln,B | Demoted to reserve roster | | | Before |
| 5/17/2012 | DUR | Nelson | Promoted to active roster | | | Before |
| 5/17/2012 | DUR | Solano,D | Demoted to reserve roster | | | Before |
| 5/17/2012 | DUR | Solano,D | Promoted to active roster | | | Before |
| 5/17/2012 | NHP | Garcia | Demoted to reserve roster | | | Before |
| 5/17/2012 | SFS | Janish | Promoted to active roster | | | Before |
| 5/17/2012 | SFS | Ramos,W | Demoted to reserve roster | | | Before |
| 5/17/2012 | TOR | Fien | Demoted to reserve roster | | | Before |
| 5/17/2012 | TOR | Locke | Promoted to active roster | | | Before |
| 5/19/2012 | DSP | Cardenas | Traded away | MAN | | After |
| 5/19/2012 | DSP | Herrera | Acquired via trade | MAN | | After |
| 5/19/2012 | MAN | Belisle | Acquired via trade | WTB | | After |
| 5/19/2012 | MAN | Cardenas | Acquired via trade | DSP | | After |
| 5/19/2012 | MAN | Fife | Acquired via trade | WTB | | After |
| 5/19/2012 | MAN | Hardy | Traded away | WTB | | After |
| 5/19/2012 | MAN | Herrera | Traded away | DSP | | After |
| 5/19/2012 | MAN | Schlereth | Acquired via trade | WTB | | After |
| 5/19/2012 | MAN | Sierra | Acquired via trade | WTB | | After |
| 5/19/2012 | WTB | Belisle | Traded away | MAN | | After |
| 5/19/2012 | WTB | Fife | Traded away | MAN | | After |
| 5/19/2012 | WTB | Hardy | Acquired via trade | MAN | | After |
| 5/19/2012 | WTB | Schlereth | Traded away | MAN | | After |
| 5/19/2012 | WTB | Sierra | Traded away | MAN | | After |
| 5/20/2012 | BOX | Brown,D | Promoted to active roster | | | Before |
| 5/20/2012 | BOX | Howard | Activated from disabled list | | | Before |
| 5/20/2012 | BOX | Schierholtz,N | Placed on disabled list | | 5/20/2012 | Before |
| 5/20/2012 | BOX | Segura,J | Demoted to reserve roster | | | Before |
| 5/20/2012 | CGS | Desmond | Placed on disabled list | | 5/19/2012 | Before |
| 5/20/2012 | CGS | Raburn | Promoted to active roster | | | Before |
| 5/20/2012 | DSP | Hanrahan | Demoted to reserve roster | | | Before |
| 5/20/2012 | DSP | Morse | Activated from disabled list | | | Before |
| 5/20/2012 | DUR | Lewis,C | Placed on disabled list | | 5/20/2012 | Before |
| 5/20/2012 | DUR | Walden | Promoted to active roster | | | Before |
| 5/20/2012 | MAN | Belisle | Promoted to active roster | | | Before |
| 5/20/2012 | MAN | Blackley,T | Demoted to reserve roster | | | Before |
| 5/20/2012 | MAN | Cardenas | Promoted to active roster | | | Before |
| 5/20/2012 | MAN | Cecil | Demoted to reserve roster | | | Before |
| 5/20/2012 | MAN | Fife | Promoted to active roster | | | Before |
| 5/20/2012 | MAN | Morrison | Demoted to reserve roster | | | Before |
| 5/20/2012 | MAN | Morrison | Promoted to active roster | | | Before |
| 5/20/2012 | MAN | Sierra | Demoted to reserve roster | | | Before |
| 5/20/2012 | MAN | Sierra | Promoted to active roster | | | Before |
| 5/20/2012 | MON | Delgado | Demoted to reserve roster | | | Before |
| 5/20/2012 | MON | Fiers | Activated from disabled list | | | Before |
| 5/20/2012 | PBC | Estrada | Placed on disabled list | | 5/19/2012 | Before |
| 5/20/2012 | PBC | Luebke | Promoted to active roster | | | Before |
| 5/22/2012 | DSP | Forsythe | Traded away | DUR | | After |
| 5/22/2012 | DSP | McDonald,Jo | Acquired via trade | DUR | | After |
| 5/22/2012 | DUR | Forsythe | Acquired via trade | DSP | | After |
| 5/22/2012 | DUR | McDonald,Jo | Traded away | DSP | | After |
| 5/23/2012 | ASB | Noesi | Promoted to active roster | | | Before |
| 5/23/2012 | ASB | Pomeranz,D | Placed on disabled list | | 5/23/2012 | Before |
| 5/23/2012 | CGS | Raburn | Demoted to reserve roster | | | Before |
| 5/23/2012 | CGS | Walker | Activated from disabled list | | | Before |
| 5/23/2012 | CRB | Griffin | Demoted to reserve roster | | | Before |
| 5/23/2012 | CRB | Lilly | Promoted to active roster | | | Before |
| 5/23/2012 | DEG | Santana,E | Activated from disabled list | | | Before |
| 5/23/2012 | DEG | Sheets | Demoted to reserve roster | | | Before |
| 5/23/2012 | DSP | McDonald,Jo | Demoted to reserve roster | | | Before |
| 5/23/2012 | DUR | De Vries | Promoted to active roster | | | Before |
| 5/23/2012 | DUR | Walden | Demoted to reserve roster | | | Before |
| 5/23/2012 | MAN | Anderson,BF | Promoted to active roster | | | Before |
| 5/23/2012 | MAN | Fife | Demoted to reserve roster | | | Before |
| 5/23/2012 | MAN | Ishikawa | Demoted to reserve roster | | | Before |
| 5/23/2012 | MAN | Morrison | Promoted to active roster | | | Before |
| 5/23/2012 | MAN | Pelfrey | Promoted to active roster | | | Before |
| 5/23/2012 | MAN | Zito | Demoted to reserve roster | | | Before |
| 5/25/2012 | CGS | Gonzalez,Ma | Acquired via trade | MON | | After |
| 5/25/2012 | CGS | Lobaton | Acquired via trade | MON | | After |
| 5/25/2012 | CGS | Lobaton | Acquired via trade | MON | | After |
| 5/25/2012 | DUR | Crosby | Traded away | MON | | After |
| 5/25/2012 | DUR | Crosby | Traded away | MON | | After |
| 5/25/2012 | DUR | Lobaton | Traded away | MON | | After |
| 5/25/2012 | DUR | Lobaton | Traded away | MON | | After |
| 5/25/2012 | DUR | Martin | Acquired via trade | MON | | After |
| 5/25/2012 | DUR | Martin | Acquired via trade | MON | | After |
| 5/25/2012 | MON | Crosby | Acquired via trade | DUR | | After |
| 5/25/2012 | MON | Crosby | Acquired via trade | DUR | | After |
| 5/25/2012 | MON | Gonzalez,Ma | Traded away | CGS | | After |
| 5/25/2012 | MON | Lobaton | Traded away | CGS | | After |
| 5/25/2012 | MON | Lobaton | Traded away | CGS | | After |
| 5/25/2012 | MON | Lobaton | Acquired via trade | DUR | | After |
| 5/25/2012 | MON | Lobaton | Acquired via trade | DUR | | After |
| 5/25/2012 | MON | Martin | Traded away | DUR | | After |
| 5/25/2012 | MON | Martin | Traded away | DUR | | After |
| 5/26/2012 | CGS | Ellis,M | Placed on disabled list | | 5/25/2012 | Before |
| 5/26/2012 | CGS | Raburn | Promoted to active roster | | | Before |
| 5/26/2012 | DSP | Drew,S | Demoted to reserve roster | | | Before |
| 5/26/2012 | DSP | Venable | Activated from disabled list | | | Before |
| 5/26/2012 | MON | Cobb | Activated from disabled list | | | Before |
| 5/26/2012 | MON | Doubront | Demoted to reserve roster | | | Before |
| 5/26/2012 | MON | Kottaras,G | Promoted to active roster | | | Before |
| 5/26/2012 | MON | Lobaton | Demoted to reserve roster | | | Before |
| 5/26/2012 | MON | Quintanilla,O | Promoted to active roster | | | Before |
| 5/28/2012 | CGS | Gonzalez,Ma | Acquired via trade | MON | | After |
| 5/28/2012 | MON | Gonzalez,Ma | Traded away | CGS | | After |
| 5/29/2012 | ASB | Noesi | Demoted to reserve roster | | | Before |
| 5/29/2012 | ASB | Weaver | Activated from disabled list | | | Before |
| 5/29/2012 | CGS | Lobaton | Demoted to reserve roster | | | Before |
| 5/29/2012 | DEG | Floyd | Activated from disabled list | | | Before |
| 5/29/2012 | DEG | Keuchel | Demoted to reserve roster | | | Before |
| 5/29/2012 | HOL | Detwiler | Activated from disabled list | | | Before |
| 5/29/2012 | HOL | Duffy | Demoted to reserve roster | | | Before |
| 5/29/2012 | MAN | Coleman,L | Placed on disabled list | | 5/29/2012 | Before |
| 5/29/2012 | MAN | Pryor | Promoted to active roster | | | Before |
| 5/29/2012 | MON | Cobb | Activated from disabled list | | | Before |
| 5/29/2012 | MON | Doubront | Demoted to reserve roster | | | Before |
| 5/29/2012 | MON | Kottaras,G | Promoted to active roster | | | Before |
| 5/29/2012 | MON | Quintanilla,O | Promoted to active roster | | | Before |
| 6/1/2012 | BOX | Howard | Placed on disabled list | | 6/1/2012 | Before |
| 6/1/2012 | BOX | Moustakas | Promoted to active roster | | | Before |
| 6/1/2012 | CLE | Adams,Ma | Demoted to reserve roster | | | Before |
| 6/1/2012 | CLE | Brantly | Promoted to active roster | | | Before |
| 6/1/2012 | CLE | Gearrin | Promoted to active roster | | | Before |
| 6/1/2012 | CLE | Rosenthal | Placed on disabled list | | 5/27/2012 | Before |
| 6/1/2012 | DSP | Hayes | Demoted to reserve roster | | | Before |
| 6/1/2012 | DSP | Ross,D | Promoted to active roster | | | Before |
| 6/1/2012 | DUR | Chavez,Er | Promoted to active roster | | | Before |
| 6/1/2012 | DUR | Crawford,B | Promoted to active roster | | | Before |
| 6/1/2012 | DUR | Gomez,M | Demoted to reserve roster | | | Before |
| 6/1/2012 | DUR | Gonzalez,Al | Demoted to reserve roster | | | Before |
| 6/1/2012 | DUR | LaRoche | Activated from disabled list | | | Before |
| 6/1/2012 | DUR | Solano,D | Demoted to reserve roster | | | Before |
| 6/1/2012 | MAN | Blackley,T | Promoted to active roster | | | Before |
| 6/1/2012 | MAN | Miller,A | Demoted to reserve roster | | | Before |
| 6/1/2012 | NHP | Bass | Demoted to reserve roster | | | Before |
| 6/1/2012 | NHP | Harvey | Promoted to active roster | | | Before |
| 6/1/2012 | PEA | Quintero | Promoted to active roster | | | Before |
| 6/1/2012 | PEA | Soto,G | Placed on disabled list | | 5/30/2012 | Before |
| 6/1/2012 | TOR | Fien | Promoted to active roster | | | Before |
| 6/1/2012 | TOR | Hughes,P | Demoted to reserve roster | | | Before |
| 6/1/2012 | TOR | Locke | Demoted to reserve roster | | | Before |
| 6/1/2012 | TOR | Tillman | Activated from disabled list | | | Before |
| 6/1/2012 | WTB | Lee,Cl | Placed on disabled list | | 5/31/2012 | Before |
| 6/1/2012 | WTB | Volstad | Promoted to active roster | | | Before |
| 6/4/2012 | ASB | Napoli | Placed on disabled list | | 6/4/2012 | Before |
| 6/4/2012 | ASB | Nieves,W | Promoted to active roster | | | Before |
| 6/4/2012 | ASB | Smyly | Activated from disabled list | | | Before |
| 6/4/2012 | ASB | Weaver | Placed on disabled list | | 6/2/2012 | Before |
| 6/4/2012 | AVA | Holland,D | Placed on disabled list | | 6/4/2012 | Before |
| 6/4/2012 | AVA | Uribe | Promoted to active roster | | | Before |
| 6/4/2012 | CLE | Hutchison | Demoted to reserve roster | | | Before |
| 6/4/2012 | CLE | Lynn,L | Activated from disabled list | | | Before |
| 6/4/2012 | CRB | Griffin | Promoted to active roster | | | Before |
| 6/4/2012 | CRB | Strasburg | Placed on disabled list | | 6/2/2012 | Before |
| 6/4/2012 | DEG | Gorzelanny | Placed on disabled list | | 6/3/2012 | Before |
| 6/4/2012 | DEG | Keuchel | Promoted to active roster | | | Before |
| 6/4/2012 | MAN | Pelfrey | Demoted to reserve roster | | | Before |
| 6/4/2012 | MAN | Zito | Promoted to active roster | | | Before |
| 6/4/2012 | NHP | Bass | Promoted to active roster | | | Before |
| 6/4/2012 | NHP | Harvey | Demoted to reserve roster | | | Before |
| 6/4/2012 | TOR | Hughes,P | Promoted to active roster | | | Before |
| 6/4/2012 | TOR | Norris,B | Demoted to reserve roster | | | Before |
| 6/4/2012 | WTB | Arias | Promoted to active roster | | | Before |
| 6/4/2012 | WTB | Dominguez | Demoted to reserve roster | | | Before |
| 6/7/2012 | CGS | Escobar,E | Demoted to reserve roster | | | Before |
| 6/7/2012 | CGS | Reynolds,MA | Promoted to active roster | | | Before |
| 6/7/2012 | DSP | Corbin | Placed on disabled list | | 6/2/2012 | Before |
| 6/7/2012 | DSP | Villanueva | Promoted to active roster | | | Before |
| 6/7/2012 | MAN | Lough | Promoted to active roster | | | Before |
| 6/7/2012 | MAN | Span | Placed on disabled list | | 6/6/2012 | Before |
| 6/7/2012 | NHP | Bass | Demoted to reserve roster | | | Before |
| 6/7/2012 | NHP | Harvey | Promoted to active roster | | | Before |
| 6/7/2012 | PEA | Haren | Activated from disabled list | | | Before |
| 6/7/2012 | PEA | Swarzak | Demoted to reserve roster | | | Before |
| 6/7/2012 | SFS | Ambriz | Demoted to reserve roster | | | Before |
| 6/9/2012 | CGS | Kelly,C | Traded away | DUR | | After |
| 6/9/2012 | CGS | LaRoche | Acquired via trade | DUR | | After |
| 6/9/2012 | DUR | Kelly,C | Acquired via trade | CGS | | After |
| 6/9/2012 | DUR | LaRoche | Traded away | CGS | | After |
| 6/10/2012 | CGS | Chisenhall | Demoted to reserve roster | | | Before |
| 6/10/2012 | CGS | Desmond | Activated from disabled list | | | Before |
| 6/10/2012 | CGS | Reynolds,MA | Demoted to reserve roster | | | Before |
| 6/10/2012 | DUR | De Vries | Demoted to reserve roster | | | Before |
| 6/10/2012 | DUR | Lewis,C | Activated from disabled list | | | Before |
| 6/10/2012 | DUR | Nava | Promoted to active roster | | | Before |
| 6/10/2012 | PBC | Rodriguez,Al | Activated from disabled list | | | Before |
| 6/10/2012 | PBC | Young,D | Demoted to reserve roster | | | Before |
| 6/10/2012 | TOR | Kearns | Demoted to reserve roster | | | Before |
| 6/10/2012 | TOR | Schumaker | Promoted to active roster | | | Before |
| 6/11/2012 | BOX | Brown,D | Demoted to reserve roster | | | Before |
| 6/11/2012 | BOX | Schierholtz,N | Activated from disabled list | | | Before |
| 6/12/2012 | CRB | Amarista,A | Traded away | MAN | | After |
| 6/12/2012 | CRB | Hoover | Acquired via trade | MAN | | After |
| 6/12/2012 | CRB | Pennington | Acquired via trade | MAN | | After |
| 6/12/2012 | CRB | Ramos,C | Traded away | MAN | | After |
| 6/12/2012 | DUR | Ishikawa | Acquired via trade | MAN | | After |
| 6/12/2012 | MAN | Amarista,A | Acquired via trade | CRB | | After |
| 6/12/2012 | MAN | Hoover | Traded away | CRB | | After |
| 6/12/2012 | MAN | Ishikawa | Traded away | DUR | | After |
| 6/12/2012 | MAN | Pennington | Traded away | CRB | | After |
| 6/12/2012 | MAN | Ramos,C | Acquired via trade | CRB | | After |
| 6/13/2012 | AUR | Albers,M | Demoted to reserve roster | | | Before |
| 6/13/2012 | AUR | Brothers | Promoted to active roster | | | Before |
| 6/13/2012 | AUR | Buck,J | Activated from disabled list | | | Before |
| 6/13/2012 | AUR | Francis | Placed on disabled list | | 6/8/2012 | Before |
| 6/13/2012 | AUR | Jackson,E | Activated from disabled list | | | Before |
| 6/13/2012 | AUR | Johnson,S | Activated from disabled list | | | Before |
| 6/13/2012 | AUR | Mathis | Demoted to reserve roster | | | Before |
| 6/13/2012 | AUR | McGehee,C | Demoted to reserve roster | | | Before |
| 6/13/2012 | AUR | Mijares,J | Demoted to reserve roster | | | Before |
| 6/13/2012 | AUR | Tracy | Promoted to active roster | | | Before |
| 6/13/2012 | AVA | Hart | Placed on disabled list | | 6/11/2012 | Before |
| 6/13/2012 | AVA | Kalish | Promoted to active roster | | | Before |
| 6/13/2012 | CGS | Ellis,M | Activated from disabled list | | | Before |
| 6/13/2012 | CGS | Gonzalez,Ma | Demoted to reserve roster | | | Before |
| 6/13/2012 | CRB | Byrd,M | Demoted to reserve roster | | | Before |
| 6/13/2012 | MAN | Amarista,A | Promoted to active roster | | | Before |
| 6/13/2012 | MAN | Anderson,BF | Placed on disabled list | | 6/12/2012 | Before |
| 6/13/2012 | MAN | Miller,A | Promoted to active roster | | | Before |
| 6/13/2012 | SFS | Archer | Promoted to active roster | | | Before |
| 6/13/2012 | SFS | Crawford,C | Demoted to reserve roster | | | Before |
| 6/13/2012 | SFS | Donald | Promoted to active roster | | | Before |
| 6/13/2012 | SFS | Millwood | Placed on disabled list | | 6/12/2012 | Before |
| 6/16/2012 | BOX | Howard | Activated from disabled list | | | Before |
| 6/16/2012 | BOX | Moustakas | Demoted to reserve roster | | | Before |
| 6/16/2012 | TOR | Karstens | Demoted to reserve roster | | | Before |
| 6/16/2012 | TOR | Norris,B | Promoted to active roster | | | Before |
| 6/19/2012 | BOX | Paulino,F | Demoted to reserve roster | | | Before |
| 6/19/2012 | BOX | Turner,Ja | Promoted to active roster | | | Before |
| 6/19/2012 | CGS | Chisenhall | Promoted to active roster | | | Before |
| 6/19/2012 | CGS | Liriano,F | Promoted to active roster | | | Before |
| 6/19/2012 | CGS | Ramirez,Er | Demoted to reserve roster | | | Before |
| 6/19/2012 | CGS | Williams | Demoted to reserve roster | | | Before |
| 6/19/2012 | CRB | Griffin | Demoted to reserve roster | | | Before |
| 6/19/2012 | CRB | Lilly | Demoted to reserve roster | | | Before |
| 6/19/2012 | CRB | Rogers,M | Promoted to active roster | | | Before |
| 6/19/2012 | CRB | Strasburg | Activated from disabled list | | | Before |
| 6/19/2012 | DSP | Corbin | Activated from disabled list | | | Before |
| 6/19/2012 | DSP | Reimold | Demoted to reserve roster | | | Before |
| 6/19/2012 | DUR | Allen,C | Demoted to reserve roster | | | Before |
| 6/19/2012 | DUR | Hill,R | Promoted to active roster | | | Before |
| 6/19/2012 | MAN | Cecil | Promoted to active roster | | | Before |
| 6/19/2012 | MAN | Chatwood | Promoted to active roster | | | Before |
| 6/19/2012 | MAN | Friedrich | Promoted to active roster | | | Before |
| 6/19/2012 | MAN | Jimenez,U | Promoted to active roster | | | Before |
| 6/19/2012 | MAN | Lough | Placed on disabled list | | 6/19/2012 | Before |
| 6/19/2012 | MAN | Miller,A | Demoted to reserve roster | | | Before |
| 6/19/2012 | MAN | Paredes | Promoted to active roster | | | Before |
| 6/19/2012 | MAN | Ramos,C | Demoted to reserve roster | | | Before |
| 6/19/2012 | MAN | Stults,E | Placed on disabled list | | 6/19/2012 | Before |
| 6/19/2012 | MAN | Zito | Placed on disabled list | | 6/18/2012 | Before |
| 6/19/2012 | PBC | Estrada | Activated from disabled list | | | Before |
| 6/19/2012 | PBC | Luebke | Demoted to reserve roster | | | Before |
| 6/19/2012 | TOR | Locke | Promoted to active roster | | | Before |
| 6/19/2012 | TOR | Stammen | Placed on disabled list | | 6/18/2012 | Before |
| 6/21/2012 | PAW | Green,Ta | Acquired via trade | TOR | | After |
| 6/21/2012 | TOR | Green,Ta | Traded away | PAW | | After |
| 6/22/2012 | AVA | Capps,M | Demoted to reserve roster | | | Before |
| 6/22/2012 | AVA | Holland,D | Activated from disabled list | | | Before |
| 6/22/2012 | CLE | Bauer | Demoted to reserve roster | | | Before |
| 6/22/2012 | CLE | Hutchison | Promoted to active roster | | | Before |
| 6/22/2012 | CLE | Rosenthal | Activated from disabled list | | | Before |
| 6/22/2012 | CLE | Rosenthal | Demoted to reserve roster | | | Before |
| 6/22/2012 | PEA | Quintero | Demoted to reserve roster | | | Before |
| 6/22/2012 | PEA | Soto,G | Activated from disabled list | | | Before |
| 6/22/2012 | WTB | Lee,Cl | Activated from disabled list | | | Before |
| 6/22/2012 | WTB | Volstad | Demoted to reserve roster | | | Before |
| 6/25/2012 | ASB | Bedard | Demoted to reserve roster | | | Before |
| 6/25/2012 | ASB | Napoli | Activated from disabled list | | | Before |
| 6/25/2012 | ASB | Nieves,W | Demoted to reserve roster | | | Before |
| 6/25/2012 | ASB | Pomeranz,D | Activated from disabled list | | | Before |
| 6/25/2012 | ASB | Smyly | Placed on disabled list | | 6/17/2012 | Before |
| 6/25/2012 | ASB | Weaver | Activated from disabled list | | | Before |
| 6/25/2012 | AUR | Bernadina | Placed on disabled list | | 6/19/2012 | Before |
| 6/25/2012 | AUR | Buck,J | Placed on disabled list | | 6/14/2012 | Before |
| 6/25/2012 | AUR | Mathis | Promoted to active roster | | | Before |
| 6/25/2012 | AUR | Presley | Promoted to active roster | | | Before |
| 6/25/2012 | MAN | Chatwood | Demoted to reserve roster | | | Before |
| 6/25/2012 | MAN | Danks,JW | Promoted to active roster | | | Before |
| 6/25/2012 | MAN | Fife | Promoted to active roster | | | Before |
| 6/25/2012 | MAN | Valverde | Placed on disabled list | | 6/24/2012 | Before |
| 6/27/2012 | BOX | Dickey | Acquired via trade | SFS | | After |
| 6/27/2012 | BOX | Gregorius | Traded away | SFS | | After |
| 6/27/2012 | BOX | Maholm,P | Acquired via trade | SFS | | After |
| 6/27/2012 | BOX | Marson | Traded away | SFS | | After |
| 6/27/2012 | BOX | Takahashi,H | Traded away | SFS | | After |
| 6/27/2012 | BOX | Volquez | Traded away | SFS | | After |
| 6/27/2012 | BOX | Zambrano | Traded away | SFS | | After |
| 6/27/2012 | DUR | DeJesus,D | Acquired via trade | NHP | | After |
| 6/27/2012 | DUR | Pagan | Traded away | NHP | | After |
| 6/27/2012 | NHP | DeJesus,D | Traded away | DUR | | After |
| 6/27/2012 | NHP | Pagan | Acquired via trade | DUR | | After |
| 6/27/2012 | SFS | Dickey | Traded away | BOX | | After |
| 6/27/2012 | SFS | Gregorius | Acquired via trade | BOX | | After |
| 6/27/2012 | SFS | Maholm,P | Traded away | BOX | | After |
| 6/27/2012 | SFS | Marson | Acquired via trade | BOX | | After |
| 6/27/2012 | SFS | Takahashi,H | Acquired via trade | BOX | | After |
| 6/27/2012 | SFS | Volquez | Acquired via trade | BOX | | After |
| 6/27/2012 | SFS | Zambrano | Acquired via trade | BOX | | After |
| 6/28/2012 | AVA | Hart | Activated from disabled list | | | Before |
| 6/28/2012 | AVA | Kalish | Demoted to reserve roster | | | Before |
| 6/28/2012 | BOX | Feliz | Promoted to active roster | | | Before |
| 6/28/2012 | BOX | Maholm,P | Demoted to reserve roster | | | Before |
| 6/28/2012 | BOX | Storen | Demoted to reserve roster | | | Before |
| 6/28/2012 | CLE | Blackburn | Demoted to reserve roster | | | Before |
| 6/28/2012 | CLE | Grimm | Promoted to active roster | | | Before |
| 6/28/2012 | CLE | Halladay | Activated from disabled list | | | Before |
| 6/28/2012 | CLE | Hutchison | Demoted to reserve roster | | | Before |
| 6/28/2012 | CRB | De Fratus | Promoted to active roster | | | Before |
| 6/28/2012 | CRB | League,B | Demoted to reserve roster | | | Before |
| 6/28/2012 | DUR | Ishikawa | Promoted to active roster | | | Before |
| 6/28/2012 | DUR | Nava | Demoted to reserve roster | | | Before |
| 6/28/2012 | HOL | Duffy | Promoted to active roster | | | Before |
| 6/28/2012 | HOL | Parker,J | Placed on disabled list | | 6/28/2012 | Before |
| 6/28/2012 | MAN | Danks,JW | Demoted to reserve roster | | | Before |
| 6/28/2012 | MAN | Loney,J | Promoted to active roster | | | Before |
| 6/28/2012 | MAN | Sappelt | Demoted to reserve roster | | | Before |
| 6/28/2012 | MAN | Wells,R | Promoted to active roster | | | Before |
| 6/28/2012 | NHP | Garcia | Promoted to active roster | | | Before |
| 6/28/2012 | NHP | Harvey | Demoted to reserve roster | | | Before |
| 7/8/2012 | AVA | Capps,M | Promoted to active roster | | | Before |
| 7/8/2012 | AVA | Price | Placed on disabled list | | 6/30/2012 | Before |
| 7/8/2012 | CGS | Lobaton | Promoted to active roster | | | Before |
| 7/8/2012 | CGS | Mesoraco | Demoted to reserve roster | | | Before |
| 7/8/2012 | MAN | Pryor | Demoted to reserve roster | | | Before |
| 7/8/2012 | MAN | Ramos,C | Promoted to active roster | | | Before |
| 7/8/2012 | NHP | Bass | Promoted to active roster | | | Before |
| 7/8/2012 | NHP | Garcia | Demoted to reserve roster | | | Before |
| 7/8/2012 | PAW | Aumont | Demoted to reserve roster | | | Before |
| 7/8/2012 | PAW | Corporan | Demoted to reserve roster | | | Before |
| 7/8/2012 | WCM | Farnsworth | Demoted to reserve roster | | | Before |
| 7/8/2012 | WCM | Nix,L | Demoted to reserve roster | | | Before |
| 7/8/2012 | WTB | Niese | Placed on disabled list | | 7/1/2012 | Before |
| 7/8/2012 | WTB | Volstad | Promoted to active roster | | | Before |
| 7/10/2012 | CLE | Avilan | Traded away | CRB | | After |
| 7/10/2012 | CLE | Avilan | Acquired via trade | WTB | | After |
| 7/10/2012 | CLE | Betemit | Traded away | CRB | | After |
| 7/10/2012 | CLE | Betemit | Acquired via trade | WTB | | After |
| 7/10/2012 | CLE | Blackburn | Traded away | WTB | | After |
| 7/10/2012 | CLE | Capuano | Acquired via trade | WTB | | After |
| 7/10/2012 | CLE | Cruz,L | Traded away | CRB | | After |
| 7/10/2012 | CLE | Cruz,L | Acquired via trade | WTB | | After |
| 7/10/2012 | CLE | Escobar,Y | Acquired via trade | WTB | | After |
| 7/10/2012 | CLE | Espinosa | Traded away | CRB | | After |
| 7/10/2012 | CLE | Halladay | Traded away | WTB | | After |
| 7/10/2012 | CLE | Hochevar | Traded away | WTB | | After |
| 7/10/2012 | CLE | Hudson,O | Traded away | WTB | | After |
| 7/10/2012 | CLE | Johnson,Jo | Acquired via trade | WTB | | After |
| 7/10/2012 | CLE | Johnson,K | Traded away | WTB | | After |
| 7/10/2012 | CLE | Jones,C | Acquired via trade | CRB | | After |
| 7/10/2012 | CLE | Mayberry | Traded away | WTB | | After |
| 7/10/2012 | CLE | Putz | Acquired via trade | WTB | | After |
| 7/10/2012 | CLE | Roenicke | Acquired via trade | CRB | | After |
| 7/10/2012 | CLE | Trout | Acquired via trade | WTB | | After |
| 7/10/2012 | CLE | Utley | Acquired via trade | WTB | | After |
| 7/10/2012 | CLE | Volstad | Acquired via trade | WTB | | After |
| 7/10/2012 | CLE | Wilhelmsen | Traded away | CRB | | After |
| 7/10/2012 | CLE | Willingham | Traded away | CRB | | After |
| 7/10/2012 | CLE | Willingham | Acquired via trade | WTB | | After |
| 7/10/2012 | CRB | Avilan | Acquired via trade | CLE | | After |
| 7/10/2012 | CRB | Betemit | Acquired via trade | CLE | | After |
| 7/10/2012 | CRB | Byrd,M | Traded away | MAN | | After |
| 7/10/2012 | CRB | Castillo | Acquired via trade | MAN | | After |
| 7/10/2012 | CRB | Clevenger | Traded away | MAN | | After |
| 7/10/2012 | CRB | Cruz,L | Acquired via trade | CLE | | After |
| 7/10/2012 | CRB | Espinosa | Acquired via trade | CLE | | After |
| 7/10/2012 | CRB | Jones,C | Traded away | CLE | | After |
| 7/10/2012 | CRB | Ramirez,Al | Traded away | MAN | | After |
| 7/10/2012 | CRB | Roenicke | Traded away | CLE | | After |
| 7/10/2012 | CRB | Shaw | Traded away | MAN | | After |
| 7/10/2012 | CRB | Stults,E | Acquired via trade | MAN | | After |
| 7/10/2012 | CRB | Wilhelmsen | Acquired via trade | CLE | | After |
| 7/10/2012 | CRB | Willingham | Acquired via trade | CLE | | After |
| 7/10/2012 | DEG | Furbush | Traded away | PBC | | After |
| 7/10/2012 | DUR | Chavez,Er | Traded away | TOR | | After |
| 7/10/2012 | DUR | Dozier | Acquired via trade | MAN | | After |
| 7/10/2012 | DUR | Hill,R | Traded away | MAN | | After |
| 7/10/2012 | DUR | Infante,O | Traded away | MAN | | After |
| 7/10/2012 | DUR | Kennedy.A | Acquired via trade | TOR | | After |
| 7/10/2012 | DUR | Lewis,C | Traded away | TOR | | After |
| 7/10/2012 | DUR | Norris,B | Acquired via trade | TOR | | After |
| 7/10/2012 | DUR | Wright,W | Traded away | TOR | | After |
| 7/10/2012 | MAN | Blackley,T | Traded away | WTB | | After |
| 7/10/2012 | MAN | Byrd,M | Acquired via trade | CRB | | After |
| 7/10/2012 | MAN | Castillo | Traded away | CRB | | After |
| 7/10/2012 | MAN | Clevenger | Acquired via trade | CRB | | After |
| 7/10/2012 | MAN | Dozier | Traded away | DUR | | After |
| 7/10/2012 | MAN | Font | Acquired via trade | WTB | | After |
| 7/10/2012 | MAN | Hill,R | Acquired via trade | DUR | | After |
| 7/10/2012 | MAN | Infante,O | Acquired via trade | DUR | | After |
| 7/10/2012 | MAN | Ramirez,Al | Acquired via trade | CRB | | After |
| 7/10/2012 | MAN | Shaw | Acquired via trade | CRB | | After |
| 7/10/2012 | MAN | Stults,E | Traded away | CRB | | After |
| 7/10/2012 | PBC | Furbush | Acquired via trade | DEG | | After |
| 7/10/2012 | PBC | Hardy | Acquired via trade | WTB | | After |
| 7/10/2012 | PBC | Johnson,Re | Traded away | WTB | | After |
| 7/10/2012 | TOR | Chavez,Er | Acquired via trade | DUR | | After |
| 7/10/2012 | TOR | Kennedy.A | Traded away | DUR | | After |
| 7/10/2012 | TOR | Lewis,C | Acquired via trade | DUR | | After |
| 7/10/2012 | TOR | Norris,B | Traded away | DUR | | After |
| 7/10/2012 | TOR | Wright,W | Acquired via trade | DUR | | After |
| 7/10/2012 | WTB | Avilan | Traded away | CLE | | After |
| 7/10/2012 | WTB | Betemit | Traded away | CLE | | After |
| 7/10/2012 | WTB | Blackburn | Acquired via trade | CLE | | After |
| 7/10/2012 | WTB | Blackley,T | Acquired via trade | MAN | | After |
| 7/10/2012 | WTB | Capuano | Traded away | CLE | | After |
| 7/10/2012 | WTB | Cruz,L | Traded away | CLE | | After |
| 7/10/2012 | WTB | Escobar,Y | Traded away | CLE | | After |
| 7/10/2012 | WTB | Font | Traded away | MAN | | After |
| 7/10/2012 | WTB | Halladay | Acquired via trade | CLE | | After |
| 7/10/2012 | WTB | Hardy | Traded away | PBC | | After |
| 7/10/2012 | WTB | Hochevar | Acquired via trade | CLE | | After |
| 7/10/2012 | WTB | Hudson,O | Acquired via trade | CLE | | After |
| 7/10/2012 | WTB | Johnson,Jo | Traded away | CLE | | After |
| 7/10/2012 | WTB | Johnson,K | Acquired via trade | CLE | | After |
| 7/10/2012 | WTB | Johnson,Re | Acquired via trade | PBC | | After |
| 7/10/2012 | WTB | Mayberry | Acquired via trade | CLE | | After |
| 7/10/2012 | WTB | Putz | Traded away | CLE | | After |
| 7/10/2012 | WTB | Trout | Traded away | CLE | | After |
| 7/10/2012 | WTB | Utley | Traded away | CLE | | After |
| 7/10/2012 | WTB | Volstad | Traded away | CLE | | After |
| 7/10/2012 | WTB | Willingham | Traded away | CLE | | After |
| 7/11/2012 | BOX | Maholm,P | Promoted to active roster | | | Before |
| 7/11/2012 | BOX | Turner,Ja | Demoted to reserve roster | | | Before |
| 7/11/2012 | CGS | Ellis,M | Placed on disabled list | | 7/11/2012 | Before |
| 7/11/2012 | CGS | Escobar,E | Promoted to active roster | | | Before |
| 7/11/2012 | CLE | Escobar,Y | Demoted to reserve roster | | | Before |
| 7/11/2012 | CLE | Roenicke | Demoted to reserve roster | | | Before |
| 7/11/2012 | CLE | Volstad | Demoted to reserve roster | | | Before |
| 7/11/2012 | CRB | Castillo | Demoted to reserve roster | | | Before |
| 7/11/2012 | CRB | Choate,R | Demoted to reserve roster | | | Before |
| 7/11/2012 | CRB | De Fratus | Demoted to reserve roster | | | Before |
| 7/11/2012 | CRB | Griffin | Promoted to active roster | | | Before |
| 7/11/2012 | CRB | Rogers,M | Demoted to reserve roster | | | Before |
| 7/11/2012 | CRB | Turner,Ju | Demoted to reserve roster | | | Before |
| 7/11/2012 | DEG | Gorzelanny | Activated from disabled list | | | Before |
| 7/11/2012 | DUR | Walden | Promoted to active roster | | | Before |
| 7/11/2012 | MAN | Cardenas | Demoted to reserve roster | | | Before |
| 7/11/2012 | MAN | Cecil | Demoted to reserve roster | | | Before |
| 7/11/2012 | MAN | Clevenger | Promoted to active roster | | | Before |
| 7/11/2012 | MAN | Coleman,L | Activated from disabled list | | | Before |
| 7/11/2012 | MAN | Fife | Demoted to reserve roster | | | Before |
| 7/11/2012 | MAN | Fife | Promoted to active roster | | | Before |
| 7/11/2012 | MAN | Friedrich | Demoted to reserve roster | | | Before |
| 7/11/2012 | MAN | Hill,R | Demoted to reserve roster | | | Before |
| 7/11/2012 | MAN | Miller,A | Promoted to active roster | | | Before |
| 7/11/2012 | MAN | Paredes | Demoted to reserve roster | | | Before |
| 7/11/2012 | MAN | Span | Activated from disabled list | | | Before |
| 7/11/2012 | MAN | Valverde | Activated from disabled list | | | Before |
| 7/11/2012 | MAN | Wells,R | Demoted to reserve roster | | | Before |
| 7/11/2012 | MAN | Zito | Activated from disabled list | | | Before |
| 7/11/2012 | NHP | Bass | Demoted to reserve roster | | | Before |
| 7/11/2012 | NHP | Garcia | Promoted to active roster | | | Before |
| 7/11/2012 | NHP | Harvey | Promoted to active roster | | | Before |
| 7/11/2012 | NHP | Valdes,R | Demoted to reserve roster | | | Before |
| 7/11/2012 | PBC | Furbush | Demoted to reserve roster | | | Before |
| 7/11/2012 | PBC | Furbush | Promoted to active roster | | | Before |
| 7/11/2012 | PBC | Kontos | Demoted to reserve roster | | | Before |
| 7/11/2012 | PBC | Lyon,B | Demoted to reserve roster | | | Before |
| 7/11/2012 | PBC | Lyon,B | Promoted to active roster | | | Before |
| 7/11/2012 | PBC | Moore,T | Promoted to active roster | | | Before |
| 7/11/2012 | PBC | Parra,G | Demoted to reserve roster | | | Before |
| 7/11/2012 | PBC | Peralta,Jh | Demoted to reserve roster | | | Before |
| 7/11/2012 | PBC | Snider,T | Promoted to active roster | | | Before |
| 7/11/2012 | TOR | Karstens | Promoted to active roster | | | Before |
| 7/11/2012 | TOR | Kearns | Promoted to active roster | | | Before |
| 7/11/2012 | TOR | Lewis,C | Demoted to reserve roster | | | Before |
| 7/11/2012 | TOR | Locke | Demoted to reserve roster | | | Before |
| 7/11/2012 | TOR | Schumaker | Demoted to reserve roster | | | Before |
| 7/11/2012 | TOR | Stammen | Activated from disabled list | | | Before |
| 7/11/2012 | WTB | Blackburn | Promoted to active roster | | | Before |
| 7/11/2012 | WTB | Hechavarria | Promoted to active roster | | | Before |
| 7/11/2012 | WTB | Hudson,O | Promoted to active roster | | | Before |
| 7/11/2012 | WTB | Treanor | Promoted to active roster | | | Before |
| 7/11/2012 | WTB | Wheeler,R | Promoted to active roster | | | Before |
| 7/13/2012 | BOX | Parmelee | Traded away | WTB | | After |
| 7/13/2012 | WTB | Parmelee | Acquired via trade | BOX | | After |
| 7/14/2012 | CLE | Escobar,Y | Promoted to active roster | | | Before |
| 7/14/2012 | CLE | Grimm | Demoted to reserve roster | | | Before |
| 7/14/2012 | CLE | Liddi | Demoted to reserve roster | | | Before |
| 7/14/2012 | CLE | Roenicke | Promoted to active roster | | | Before |
| 7/14/2012 | DUR | De Vries | Promoted to active roster | | | Before |
| 7/14/2012 | DUR | Walden | Demoted to reserve roster | | | Before |
| 7/14/2012 | HOL | Duffy | Demoted to reserve roster | | | Before |
| 7/14/2012 | HOL | Parker,J | Activated from disabled list | | | Before |
| 7/14/2012 | HOL | Rodriguez,P | Promoted to active roster | | | Before |
| 7/14/2012 | HOL | Uehara | Demoted to reserve roster | | | Before |
| 7/14/2012 | MAN | Byrd,M | Promoted to active roster | | | Before |
| 7/14/2012 | MAN | Hafner | Placed on disabled list | | 7/13/2012 | Before |
| 7/14/2012 | MAN | Jimenez,U | Demoted to reserve roster | | | Before |
| 7/14/2012 | MAN | Shaw | Promoted to active roster | | | Before |
| 7/14/2012 | PBC | Kontos | Promoted to active roster | | | Before |
| 7/14/2012 | PBC | Masterson | Demoted to reserve roster | | | Before |
| 7/14/2012 | PBC | Niemann | Promoted to active roster | | | Before |
| 7/14/2012 | PBC | Strop | Demoted to reserve roster | | | Before |
| 7/14/2012 | TOR | Fien | Demoted to reserve roster | | | Before |
| 7/14/2012 | TOR | Wright,W | Promoted to active roster | | | Before |
| 7/14/2012 | WCM | Jepsen | Promoted to active roster | | | Before |
| 7/14/2012 | WCM | Markakis | Activated from disabled list | | | Before |
| 7/16/2012 | CLE | Barton | Acquired via trade | TOR | | After |
| 7/16/2012 | CLE | Escobar,Y | Traded away | MAN | | After |
| 7/16/2012 | CLE | Lombardozzi | Traded away | TOR | | After |
| 7/16/2012 | CLE | Nieuwenhuis | Traded away | MAN | | After |
| 7/16/2012 | CLE | Pacheco | Traded away | MON | | After |
| 7/16/2012 | CLE | Podsednik | Acquired via trade | MON | | After |
| 7/16/2012 | CLE | Putz | Traded away | MON | | After |
| 7/16/2012 | CLE | Ramirez,Al | Acquired via trade | MAN | | After |
| 7/16/2012 | CLE | Volstad | Traded away | TOR | | After |
| 7/16/2012 | CLE | Wright,W | Acquired via trade | TOR | | After |
| 7/16/2012 | MAN | Escobar,Y | Acquired via trade | CLE | | After |
| 7/16/2012 | MAN | Nieuwenhuis | Acquired via trade | CLE | | After |
| 7/16/2012 | MAN | Ramirez,Al | Traded away | CLE | | After |
| 7/16/2012 | MON | Pacheco | Acquired via trade | CLE | | After |
| 7/16/2012 | MON | Podsednik | Traded away | CLE | | After |
| 7/16/2012 | MON | Putz | Acquired via trade | CLE | | After |
| 7/16/2012 | TOR | Barton | Traded away | CLE | | After |
| 7/16/2012 | TOR | Lombardozzi | Acquired via trade | CLE | | After |
| 7/16/2012 | TOR | Volstad | Acquired via trade | CLE | | After |
| 7/16/2012 | TOR | Wright,W | Traded away | CLE | | After |
| 7/17/2012 | AVA | Kinney | Demoted to reserve roster | | | Before |
| 7/17/2012 | AVA | Price | Activated from disabled list | | | Before |
| 7/17/2012 | CLE | Barton | Promoted to active roster | | | Before |
| 7/17/2012 | CLE | Hosmer | Promoted to active roster | | | Before |
| 7/17/2012 | CLE | Martin,Le | Promoted to active roster | | | Before |
| 7/17/2012 | CLE | Podsednik | Promoted to active roster | | | Before |
| 7/17/2012 | CLE | Valdespin | Placed on disabled list | | 7/15/2012 | Before |
| 7/17/2012 | DEG | Bell,H | Promoted to active roster | | | Before |
| 7/17/2012 | DEG | Mazzaro | Promoted to active roster | | | Before |
| 7/17/2012 | DEG | Peralta,W | Demoted to reserve roster | | | Before |
| 7/17/2012 | DEG | Santana,E | Placed on disabled list | | 7/17/2012 | Before |
| 7/17/2012 | DUR | De Vries | Demoted to reserve roster | | | Before |
| 7/17/2012 | DUR | Lincoln,B | Promoted to active roster | | | Before |
| 7/17/2012 | MAN | Bourjos | Demoted to reserve roster | | | Before |
| 7/17/2012 | MAN | Chatwood | Promoted to active roster | | | Before |
| 7/17/2012 | MAN | Ramos,C | Demoted to reserve roster | | | Before |
| 7/17/2012 | MON | Berkman | Demoted to reserve roster | | | Before |
| 7/17/2012 | MON | Ramirez,R | Demoted to reserve roster | | | Before |
| 7/17/2012 | PBC | Masterson | Promoted to active roster | | | Before |
| 7/17/2012 | PBC | Niemann | Demoted to reserve roster | | | Before |
| 7/17/2012 | TOR | Fien | Promoted to active roster | | | Before |
| 7/17/2012 | TOR | Karstens | Demoted to reserve roster | | | Before |
| 7/17/2012 | TOR | Lewis,C | Promoted to active roster | | | Before |
| 7/17/2012 | TOR | Lombardozzi | Demoted to reserve roster | | | Before |
| 7/17/2012 | TOR | Volstad | Demoted to reserve roster | | | Before |
| 7/17/2012 | TOR | Volstad | Promoted to active roster | | | Before |
| 7/17/2012 | WTB | Arias | Placed on disabled list | | 7/13/2012 | Before |
| 7/17/2012 | WTB | Niese | Activated from disabled list | | | Before |
| 7/17/2012 | WTB | Paul | Demoted to reserve roster | | | Before |
| 7/19/2012 | MON | Lee,Cl | Acquired via trade | WTB | | After |
| 7/19/2012 | MON | Lowe,D | Traded away | WTB | | After |
| 7/19/2012 | MON | Richards | Traded away | WTB | | After |
| 7/19/2012 | WTB | Lee,Cl | Traded away | MON | | After |
| 7/19/2012 | WTB | Lowe,D | Acquired via trade | MON | | After |
| 7/19/2012 | WTB | Richards | Acquired via trade | MON | | After |
| 7/20/2012 | CLE | Garcia,C | Promoted to active roster | | | Before |
| 7/20/2012 | CLE | Gearrin | Demoted to reserve roster | | | Before |
| 7/20/2012 | DSP | Berry | Demoted to reserve roster | | | Before |
| 7/20/2012 | DSP | McDonald,Jo | Promoted to active roster | | | Before |
| 7/20/2012 | DSP | Ogando | Demoted to reserve roster | | | Before |
| 7/20/2012 | DSP | Reimold | Promoted to active roster | | | Before |
| 7/20/2012 | MAN | Anderson,BF | Activated from disabled list | | | Before |
| 7/20/2012 | MAN | Miller,A | Demoted to reserve roster | | | Before |
| 7/20/2012 | MON | Lee,Cl | Placed on disabled list | | 7/17/2012 | Before |
| 7/20/2012 | PBC | Masterson | Demoted to reserve roster | | | Before |
| 7/20/2012 | PBC | Niemann | Promoted to active roster | | | Before |
| 7/20/2012 | PBC | Rodriguez,Al | Placed on disabled list | | 7/20/2012 | Before |
| 7/20/2012 | PBC | Young,D | Promoted to active roster | | | Before |
| 7/20/2012 | WTB | Lowe,D | Promoted to active roster | | | Before |
| 7/20/2012 | WTB | Parmelee | Promoted to active roster | | | Before |
| 7/20/2012 | WTB | Richards | Promoted to active roster | | | Before |
| 7/22/2012 | DEG | Ryan | Traded away | DUR | | After |
| 7/22/2012 | DUR | Ryan | Acquired via trade | DEG | | After |
| 7/22/2012 | PEA | Brantley | Acquired via trade | TOR | | After |
| 7/22/2012 | PEA | Colvin | Traded away | TOR | | After |
| 7/22/2012 | TOR | Brantley | Traded away | PEA | | After |
| 7/22/2012 | TOR | Colvin | Acquired via trade | PEA | | After |
| 7/23/2012 | BOX | Feliz | Demoted to reserve roster | | | Before |
| 7/23/2012 | BOX | Storen | Promoted to active roster | | | Before |
| 7/23/2012 | DEG | Santiago,R | Promoted to active roster | | | Before |
| 7/23/2012 | DUR | Ishikawa | Demoted to reserve roster | | | Before |
| 7/23/2012 | DUR | Nelson | Demoted to reserve roster | | | Before |
| 7/23/2012 | DUR | Solano,D | Promoted to active roster | | | Before |
| 7/23/2012 | HOL | Layne | Demoted to reserve roster | | | Before |
| 7/23/2012 | HOL | Neshek | Promoted to active roster | | | Before |
| 7/23/2012 | MAN | Fife | Demoted to reserve roster | | | Before |
| 7/23/2012 | MAN | Guerra | Promoted to active roster | | | Before |
| 7/23/2012 | MAN | Hill,R | Promoted to active roster | | | Before |
| 7/23/2012 | MAN | Shaw | Demoted to reserve roster | | | Before |
| 7/23/2012 | PBC | Masterson | Promoted to active roster | | | Before |
| 7/23/2012 | PBC | Niemann | Demoted to reserve roster | | | Before |
| 7/23/2012 | PEA | Andino | Promoted to active roster | | | Before |
| 7/23/2012 | PEA | Horst | Demoted to reserve roster | | | Before |
| 7/23/2012 | PEA | Pedroia | Placed on disabled list | | 7/23/2012 | Before |
| 7/23/2012 | PEA | Reed | Promoted to active roster | | | Before |
| 7/25/2012 | CGS | Hudson,T | Acquired via trade | PEA | | After |
| 7/25/2012 | CGS | Humber | Traded away | PEA | | After |
| 7/25/2012 | CGS | Johnson,Ro | Traded away | PEA | | After |
| 7/25/2012 | CGS | Raburn | Traded away | PEA | | After |
| 7/25/2012 | CGS | Rolen | Traded away | PEA | | After |
| 7/25/2012 | CRB | Blevins | Acquired via trade | PAW | | After |
| 7/25/2012 | CRB | Choate,R | Traded away | PAW | | After |
| 7/25/2012 | CRB | Corporan | Acquired via trade | PAW | | After |
| 7/25/2012 | CRB | Johnson,E | Acquired via trade | PAW | | After |
| 7/25/2012 | CRB | Leroux | Traded away | PAW | | After |
| 7/25/2012 | CRB | Schneider | Acquired via trade | HOL | | After |
| 7/25/2012 | CRB | Turner,Ju | Traded away | PAW | | After |
| 7/25/2012 | CRB | Wilson,Bo | Traded away | PAW | | After |
| 7/25/2012 | DUR | Flaherty | Acquired via trade | PBC | | After |
| 7/25/2012 | DUR | Hairston,S | Traded away | PBC | | After |
| 7/25/2012 | DUR | Nelson | Traded away | PBC | | After |
| 7/25/2012 | DUR | Snider,T | Acquired via trade | PBC | | After |
| 7/25/2012 | HOL | Schneider | Traded away | CRB | | After |
| 7/25/2012 | MAN | Cardenas | Traded away | PAW | | After |
| 7/25/2012 | MAN | Guerra | Traded away | PAW | | After |
| 7/25/2012 | MAN | Miller,A | Traded away | PAW | | After |
| 7/25/2012 | MAN | Paredes | Traded away | PAW | | After |
| 7/25/2012 | MAN | Schlereth | Traded away | PAW | | After |
| 7/25/2012 | MAN | Wells,R | Traded away | PAW | | After |
| 7/25/2012 | MAN | Zito | Traded away | PAW | | After |
| 7/25/2012 | PAW | Blevins | Traded away | CRB | | After |
| 7/25/2012 | PAW | Cardenas | Acquired via trade | MAN | | After |
| 7/25/2012 | PAW | Choate,R | Acquired via trade | CRB | | After |
| 7/25/2012 | PAW | Corporan | Traded away | CRB | | After |
| 7/25/2012 | PAW | Guerra | Acquired via trade | MAN | | After |
| 7/25/2012 | PAW | Johnson,E | Traded away | CRB | | After |
| 7/25/2012 | PAW | Leroux | Acquired via trade | CRB | | After |
| 7/25/2012 | PAW | Miller,A | Acquired via trade | MAN | | After |
| 7/25/2012 | PAW | Paredes | Acquired via trade | MAN | | After |
| 7/25/2012 | PAW | Schlereth | Acquired via trade | MAN | | After |
| 7/25/2012 | PAW | Turner,Ju | Acquired via trade | CRB | | After |
| 7/25/2012 | PAW | Wells,R | Acquired via trade | MAN | | After |
| 7/25/2012 | PAW | Wilson,Bo | Acquired via trade | CRB | | After |
| 7/25/2012 | PAW | Zito | Acquired via trade | MAN | | After |
| 7/25/2012 | PBC | Callaspo | Acquired via trade | PEA | | After |
| 7/25/2012 | PBC | Flaherty | Traded away | DUR | | After |
| 7/25/2012 | PBC | Hairston,S | Acquired via trade | DUR | | After |
| 7/25/2012 | PBC | Nelson | Acquired via trade | DUR | | After |
| 7/25/2012 | PBC | Schafer,L | Traded away | PEA | | After |
| 7/25/2012 | PBC | Snider,T | Traded away | DUR | | After |
| 7/25/2012 | PEA | Callaspo | Traded away | PBC | | After |
| 7/25/2012 | PEA | Hudson,T | Traded away | CGS | | After |
| 7/25/2012 | PEA | Humber | Acquired via trade | CGS | | After |
| 7/25/2012 | PEA | Johnson,Ro | Acquired via trade | CGS | | After |
| 7/25/2012 | PEA | Raburn | Acquired via trade | CGS | | After |
| 7/25/2012 | PEA | Rolen | Acquired via trade | CGS | | After |
| 7/25/2012 | PEA | Schafer,L | Acquired via trade | PBC | | After |
| 7/26/2012 | AVA | Fontenot | Demoted to reserve roster | | | Before |
| 7/26/2012 | AVA | Storey | Promoted to active roster | | | Before |
| 7/26/2012 | BOX | Moustakas | Promoted to active roster | | | Before |
| 7/26/2012 | BOX | Storen | Demoted to reserve roster | | | Before |
| 7/26/2012 | CGS | Liriano,F | Demoted to reserve roster | | | Before |
| 7/26/2012 | CRB | Blevins | Demoted to reserve roster | | | Before |
| 7/26/2012 | CRB | Griffin | Demoted to reserve roster | | | Before |
| 7/26/2012 | CRB | Johnson,E | Demoted to reserve roster | | | Before |
| 7/26/2012 | CRB | Schneider | Promoted to active roster | | | Before |
| 7/26/2012 | CRB | Stults,E | Activated from disabled list | | | Before |
| 7/26/2012 | DSP | Adams,Mi | Promoted to active roster | | | Before |
| 7/26/2012 | DSP | Hanrahan | Promoted to active roster | | | Before |
| 7/26/2012 | DSP | Reimold | Demoted to reserve roster | | | Before |
| 7/26/2012 | DSP | Rodriguez,H | Demoted to reserve roster | | | Before |
| 7/26/2012 | DUR | Flaherty | Promoted to active roster | | | Before |
| 7/26/2012 | DUR | Kennedy.A | Placed on disabled list | | 7/24/2012 | Before |
| 7/26/2012 | HOL | Bundy | Signed | | | Before |
| 7/26/2012 | HOL | Cedeno,R | Promoted to active roster | | | Before |
| 7/26/2012 | HOL | Cozart | Placed on disabled list | | 7/26/2012 | Before |
| 7/26/2012 | MAN | Cecil | Promoted to active roster | | | Before |
| 7/26/2012 | MAN | Chatwood | Demoted to reserve roster | | | Before |
| 7/26/2012 | MAN | Cooper | Demoted to reserve roster | | | Before |
| 7/26/2012 | MAN | Danks,JW | Promoted to active roster | | | Before |
| 7/26/2012 | MAN | Jimenez,U | Promoted to active roster | | | Before |
| 7/26/2012 | MAN | Lough | Activated from disabled list | | | Before |
| 7/26/2012 | MON | Middlebrooks | Demoted to reserve roster | | | Before |
| 7/26/2012 | MON | Rutledge | Promoted to active roster | | | Before |
| 7/26/2012 | PBC | Callaspo | Demoted to reserve roster | | | Before |
| 7/26/2012 | PEA | Rolen | Promoted to active roster | | | Before |
| 7/26/2012 | PEA | Swarzak | Promoted to active roster | | | Before |
| 7/26/2012 | TOR | Fien | Demoted to reserve roster | | | Before |
| 7/26/2012 | TOR | Karstens | Promoted to active roster | | | Before |
| 7/26/2012 | TOR | Lewis,C | Demoted to reserve roster | | | Before |
| 7/26/2012 | TOR | Volstad | Promoted to active roster | | | Before |
| 7/29/2012 | AUR | Arredondo | Promoted to active roster | | | Before |
| 7/29/2012 | AUR | Bernadina | Activated from disabled list | | | Before |
| 7/29/2012 | AUR | Chen,B | Promoted to active roster | | | Before |
| 7/29/2012 | AUR | Hamels | Placed on disabled list | | 7/23/2012 | Before |
| 7/29/2012 | AUR | Johnson,S | Placed on disabled list | | 7/25/2012 | Before |
| 7/29/2012 | AUR | Revere | Placed on disabled list | | 7/28/2012 | Before |
| 7/29/2012 | BOX | McPherson | Promoted to active roster | | | Before |
| 7/29/2012 | BOX | Moustakas | Demoted to reserve roster | | | Before |
| 7/29/2012 | DEG | Hernandez,R | Promoted to active roster | | | Before |
| 7/29/2012 | DEG | Olivo | Placed on disabled list | | 7/28/2012 | Before |
| 7/29/2012 | DSP | Ogando | Promoted to active roster | | | Before |
| 7/29/2012 | DSP | Wood,T | Placed on disabled list | | 7/28/2012 | Before |
| 7/29/2012 | HOL | Parker,J | Placed on disabled list | | 7/28/2012 | Before |
| 7/29/2012 | MAN | Jimenez,U | Demoted to reserve roster | | | Before |
| 7/29/2012 | MAN | Sappelt | Promoted to active roster | | | Before |
| 7/29/2012 | NHP | Bass | Promoted to active roster | | | Before |
| 7/29/2012 | NHP | Gonzalez,Mig | Placed on disabled list | | 7/29/2012 | Before |
| 7/29/2012 | PBC | Helton | Demoted to reserve roster | | | Before |
| 7/29/2012 | PBC | Loup | Demoted to reserve roster | | | Before |
| 7/29/2012 | PBC | Masterson | Demoted to reserve roster | | | Before |
| 7/29/2012 | PBC | Nelson | Promoted to active roster | | | Before |
| 7/29/2012 | PBC | Niemann | Promoted to active roster | | | Before |
| 7/29/2012 | PBC | Strop | Promoted to active roster | | | Before |
| 8/1/2012 | ASB | Martinez,JD | Promoted to active roster | | | Before |
| 8/1/2012 | ASB | Pettitte | Demoted to reserve roster | | | Before |
| 8/1/2012 | ASB | Smyly | Activated from disabled list | | | Before |
| 8/1/2012 | ASB | Stubbs | Placed on disabled list | | 7/31/2012 | Before |
| 8/1/2012 | CGS | Ellis,M | Activated from disabled list | | | Before |
| 8/1/2012 | CGS | Escobar,E | Demoted to reserve roster | | | Before |
| 8/1/2012 | CLE | Escalona | Demoted to reserve roster | | | Before |
| 8/1/2012 | CLE | Hutchison | Promoted to active roster | | | Before |
| 8/1/2012 | CLE | Matsuzaka | Promoted to active roster | | | Before |
| 8/1/2012 | CLE | Mendoza | Placed on disabled list | | 7/24/2012 | Before |
| 8/1/2012 | CLE | Podsednik | Placed on disabled list | | 7/30/2012 | Before |
| 8/1/2012 | CLE | Ruf | Promoted to active roster | | | Before |
| 8/1/2012 | DSP | Berry | Promoted to active roster | | | Before |
| 8/1/2012 | DSP | McDonald,Jo | Demoted to reserve roster | | | Before |
| 8/1/2012 | DSP | Pearce,S | Demoted to reserve roster | | | Before |
| 8/1/2012 | DSP | Reimold | Promoted to active roster | | | Before |
| 8/1/2012 | MAN | Anderson,BF | Demoted to reserve roster | | | Before |
| 8/1/2012 | MAN | Coleman,L | Demoted to reserve roster | | | Before |
| 8/1/2012 | MAN | Pelfrey | Promoted to active roster | | | Before |
| 8/1/2012 | MAN | Ramos,C | Promoted to active roster | | | Before |
| 8/1/2012 | PBC | Callaspo | Promoted to active roster | | | Before |
| 8/1/2012 | PBC | Frandsen | Demoted to reserve roster | | | Before |
| 8/1/2012 | PBC | Helton | Promoted to active roster | | | Before |
| 8/1/2012 | PBC | Masterson | Promoted to active roster | | | Before |
| 8/1/2012 | PBC | Niemann | Demoted to reserve roster | | | Before |
| 8/1/2012 | PBC | Votto | Placed on disabled list | | 7/30/2012 | Before |
| 8/1/2012 | TOR | Galvis | Demoted to reserve roster | | | Before |
| 8/1/2012 | TOR | Galvis | Promoted to active roster | | | Before |
| 8/1/2012 | TOR | Kearns | Demoted to reserve roster | | | Before |
| 8/1/2012 | TOR | Locke | Promoted to active roster | | | Before |
| 8/1/2012 | TOR | Lombardozzi | Promoted to active roster | | | Before |
| 8/1/2012 | TOR | Tillman | Demoted to reserve roster | | | Before |
| 8/4/2012 | CLE | Hosmer | Demoted to reserve roster | | | Before |
| 8/4/2012 | CLE | Valdespin | Activated from disabled list | | | Before |
| 8/4/2012 | DUR | De Vries | Promoted to active roster | | | Before |
| 8/4/2012 | DUR | Flaherty | Demoted to reserve roster | | | Before |
| 8/4/2012 | DUR | Lincoln,B | Demoted to reserve roster | | | Before |
| 8/4/2012 | DUR | Walden | Promoted to active roster | | | Before |
| 8/4/2012 | MAN | Fife | Promoted to active roster | | | Before |
| 8/4/2012 | MAN | Hill,R | Demoted to reserve roster | | | Before |
| 8/4/2012 | MAN | Sappelt | Demoted to reserve roster | | | Before |
| 8/4/2012 | MAN | Shaw | Promoted to active roster | | | Before |
| 8/4/2012 | MON | Berkman | Promoted to active roster | | | Before |
| 8/4/2012 | MON | Quentin | Demoted to reserve roster | | | Before |
| 8/4/2012 | NHP | Beavan | Promoted to active roster | | | Before |
| 8/4/2012 | NHP | Garcia,A | Demoted to reserve roster | | | Before |
| 8/4/2012 | NHP | Garcia,A | Promoted to active roster | | | Before |
| 8/4/2012 | NHP | Harvey | Demoted to reserve roster | | | Before |
| 8/4/2012 | PEA | Humber | Promoted to active roster | | | Before |
| 8/4/2012 | PEA | Norberto | Demoted to reserve roster | | | Before |
| 8/4/2012 | WCM | Henderson | Demoted to reserve roster | | | Before |
| 8/4/2012 | WCM | Kelley,S | Promoted to active roster | | | Before |
| 8/4/2012 | WCM | Morrow | Placed on disabled list | | 7/15/2012 | Before |
| 8/4/2012 | WCM | Mortensen | Promoted to active roster | | | Before |
| 8/7/2012 | ASB | Getz | Demoted to reserve roster | | | Before |
| 8/7/2012 | CRB | Blevins | Promoted to active roster | | | Before |
| 8/7/2012 | CRB | Hoover | Demoted to reserve roster | | | Before |
| 8/7/2012 | MAN | Chatwood | Promoted to active roster | | | Before |
| 8/7/2012 | MAN | Friedrich | Promoted to active roster | | | Before |
| 8/7/2012 | MAN | Hafner | Activated from disabled list | | | Before |
| 8/7/2012 | MAN | Pelfrey | Demoted to reserve roster | | | Before |
| 8/7/2012 | MAN | Ramos,C | Demoted to reserve roster | | | Before |
| 8/7/2012 | MAN | Sierra | Placed on disabled list | | 8/7/2012 | Before |
| 8/7/2012 | MON | McAllister | Promoted to active roster | | | Before |
| 8/7/2012 | NHP | Garcia,A | Promoted to active roster | | | Before |
| 8/7/2012 | NHP | Pollock | Demoted to reserve roster | | | Before |
| 8/7/2012 | PAW | Hannahan | Demoted to reserve roster | | | Before |
| 8/7/2012 | PAW | Jurrjens | Demoted to reserve roster | | | Before |
| 8/7/2012 | PAW | Turner,Ju | Promoted to active roster | | | Before |
| 8/7/2012 | SFS | Archer | Demoted to reserve roster | | | Before |
| 8/7/2012 | SFS | Gee | Demoted to reserve roster | | | Before |
| 8/7/2012 | SFS | Lindstrom,M | Demoted to reserve roster | | | Before |
| 8/7/2012 | SFS | Resop | Promoted to active roster | | | Before |
| 8/7/2012 | SFS | Sanchez,E | Promoted to active roster | | | Before |
| 8/7/2012 | SFS | Stewart,Z | Promoted to active roster | | | Before |
| 8/7/2012 | SFS | Takahashi,H | Promoted to active roster | | | Before |
| 8/7/2012 | SFS | Volquez | Promoted to active roster | | | Before |
| 8/7/2012 | TOR | Kearns | Promoted to active roster | | | Before |
| 8/7/2012 | TOR | Plouffe | Placed on disabled list | | 8/7/2012 | Before |
| 8/7/2012 | WCM | Baxter | Demoted to reserve roster | | | Before |
| 8/10/2012 | DSP | Cabrera,Ev | Placed on disabled list | | 8/10/2012 | Before |
| 8/10/2012 | DSP | Drew,S | Promoted to active roster | | | Before |
| 8/10/2012 | DUR | Crawford,B | Demoted to reserve roster | | | Before |
| 8/10/2012 | DUR | De Vries | Demoted to reserve roster | | | Before |
| 8/10/2012 | DUR | Gomez,M | Promoted to active roster | | | Before |
| 8/10/2012 | DUR | Gonzalez,Al | Promoted to active roster | | | Before |
| 8/10/2012 | DUR | Kennedy.A | Activated from disabled list | | | Before |
| 8/10/2012 | DUR | Ryan | Demoted to reserve roster | | | Before |
| 8/10/2012 | NHP | Harvey | Promoted to active roster | | | Before |
| 8/10/2012 | NHP | Kirkman | Demoted to reserve roster | | | Before |
| 8/10/2012 | WTB | Arias | Activated from disabled list | | | Before |
| 8/10/2012 | WTB | Treanor | Demoted to reserve roster | | | Before |
| 8/13/2012 | AUR | Buck,J | Activated from disabled list | | | Before |
| 8/13/2012 | AUR | Chen,B | Demoted to reserve roster | | | Before |
| 8/13/2012 | AUR | Hamels | Activated from disabled list | | | Before |
| 8/13/2012 | AUR | Mathis | Demoted to reserve roster | | | Before |
| 8/13/2012 | AUR | McGehee,C | Promoted to active roster | | | Before |
| 8/13/2012 | AUR | Presley | Demoted to reserve roster | | | Before |
| 8/13/2012 | AUR | Revere | Activated from disabled list | | | Before |
| 8/13/2012 | AUR | Tracy | Demoted to reserve roster | | | Before |
| 8/13/2012 | BOX | McPherson | Demoted to reserve roster | | | Before |
| 8/13/2012 | BOX | Paulino,F | Promoted to active roster | | | Before |
| 8/13/2012 | CGS | Chisenhall | Demoted to reserve roster | | | Before |
| 8/13/2012 | CGS | Gonzalez,Ma | Promoted to active roster | | | Before |
| 8/13/2012 | DSP | Hellickson | Demoted to reserve roster | | | Before |
| 8/13/2012 | DSP | Wood,T | Activated from disabled list | | | Before |
| 8/13/2012 | HOL | Cozart | Activated from disabled list | | | Before |
| 8/13/2012 | HOL | Machado | Demoted to reserve roster | | | Before |
| 8/13/2012 | HOL | Neshek | Demoted to reserve roster | | | Before |
| 8/13/2012 | HOL | Parker,J | Activated from disabled list | | | Before |
| 8/13/2012 | MAN | Chatwood | Demoted to reserve roster | | | Before |
| 8/13/2012 | MAN | Coleman,L | Promoted to active roster | | | Before |
| 8/13/2012 | MAN | Fife | Demoted to reserve roster | | | Before |
| 8/13/2012 | MAN | Jimenez,U | Promoted to active roster | | | Before |
| 8/13/2012 | MAN | Lough | Demoted to reserve roster | | | Before |
| 8/13/2012 | MAN | Pryor | Promoted to active roster | | | Before |
| 8/13/2012 | TOR | Lowrie | Placed on disabled list | | 8/13/2012 | Before |
| 8/13/2012 | TOR | Schumaker | Promoted to active roster | | | Before |
| 8/16/2012 | AVA | Elbert | Demoted to reserve roster | | | Before |
| 8/16/2012 | AVA | Kalish | Promoted to active roster | | | Before |
| 8/16/2012 | AVA | Kinney | Promoted to active roster | | | Before |
| 8/16/2012 | AVA | Tulowitzki | Placed on disabled list | | 8/15/2012 | Before |
| 8/16/2012 | CRB | Griffin | Promoted to active roster | | | Before |
| 8/16/2012 | CRB | Medlen | Demoted to reserve roster | | | Before |
| 8/16/2012 | NHP | Beavan | Demoted to reserve roster | | | Before |
| 8/16/2012 | NHP | Beavan | Promoted to active roster | | | Before |
| 8/16/2012 | NHP | Gonzalez,Mig | Activated from disabled list | | | Before |
| 8/16/2012 | NHP | Harvey | Demoted to reserve roster | | | Before |
| 8/16/2012 | PEA | Andino | Demoted to reserve roster | | | Before |
| 8/16/2012 | PEA | Pedroia | Activated from disabled list | | | Before |
| 8/16/2012 | TOR | Lewis,C | Promoted to active roster | | | Before |
| 8/16/2012 | TOR | Volstad | Demoted to reserve roster | | | Before |
| 8/19/2012 | CLE | Alburquerque | Promoted to active roster | | | Before |
| 8/19/2012 | CLE | Chacin | Demoted to reserve roster | | | Before |
| 8/19/2012 | CLE | Garcia,C | Demoted to reserve roster | | | Before |
| 8/19/2012 | CLE | Mendoza | Activated from disabled list | | | Before |
| 8/19/2012 | NHP | Beavan | Demoted to reserve roster | | | Before |
| 8/19/2012 | NHP | Smoak | Promoted to active roster | | | Before |
| 8/19/2012 | PAW | Blackmon | Demoted to reserve roster | | | Before |
| 8/19/2012 | PAW | Cardenas | Promoted to active roster | | | Before |
| 8/19/2012 | PAW | Choate,R | Promoted to active roster | | | Before |
| 8/19/2012 | PAW | Dobbs | Demoted to reserve roster | | | Before |
| 8/19/2012 | PAW | Green,Ta | Promoted to active roster | | | Before |
| 8/19/2012 | PAW | Paredes | Promoted to active roster | | | Before |
| 8/22/2012 | CRB | Avilan | Demoted to reserve roster | | | Before |
| 8/22/2012 | CRB | Cruz,L | Demoted to reserve roster | | | Before |
| 8/22/2012 | CRB | De Fratus | Promoted to active roster | | | Before |
| 8/22/2012 | CRB | Griffin | Placed on disabled list | | 8/21/2012 | Before |
| 8/22/2012 | CRB | Johnson,E | Promoted to active roster | | | Before |
| 8/22/2012 | CRB | Lilly | Promoted to active roster | | | Before |
| 8/22/2012 | NHP | Gonzalez,Mig | Demoted to reserve roster | | | Before |
| 8/22/2012 | NHP | Harvey | Promoted to active roster | | | Before |
| 8/22/2012 | PBC | Crain | Demoted to reserve roster | | | Before |
| 8/22/2012 | PBC | Helton | Demoted to reserve roster | | | Before |
| 8/22/2012 | PBC | Moore,S | Demoted to reserve roster | | | Before |
| 8/22/2012 | PBC | Parra,G | Promoted to active roster | | | Before |
| 8/22/2012 | PBC | Rasmus | Promoted to active roster | | | Before |
| 8/22/2012 | PBC | Thayer | Promoted to active roster | | | Before |
| 8/22/2012 | TOR | Fien | Promoted to active roster | | | Before |
| 8/22/2012 | TOR | Karstens | Demoted to reserve roster | | | Before |
| 8/22/2012 | TOR | Locke | Demoted to reserve roster | | | Before |
| 8/22/2012 | TOR | Tillman | Promoted to active roster | | | Before |
| 8/25/2012 | BOX | Paulino,F | Demoted to reserve roster | | | Before |
| 8/25/2012 | BOX | Storen | Promoted to active roster | | | Before |
| 8/25/2012 | CGS | Ortiz | Demoted to reserve roster | | | Before |
| 8/25/2012 | CGS | Thome,J | Promoted to active roster | | | Before |
| 8/25/2012 | DSP | Hellickson | Promoted to active roster | | | Before |
| 8/25/2012 | DSP | LeBlanc | Demoted to reserve roster | | | Before |
| 8/25/2012 | NHP | Gonzalez,Mig | Promoted to active roster | | | Before |
| 8/25/2012 | NHP | Harvey | Demoted to reserve roster | | | Before |
| 8/28/2012 | AUR | Garza | Demoted to reserve roster | | | Before |
| 8/28/2012 | BBK | Eaton | Promoted to active roster | | | Before |
| 8/28/2012 | BBK | Perez,S | Demoted to reserve roster | | | Before |
| 8/28/2012 | BOX | McPherson | Promoted to active roster | | | Before |
| 8/28/2012 | BOX | Storen | Demoted to reserve roster | | | Before |
| 8/28/2012 | DSP | Cabrera,Ev | Activated from disabled list | | | Before |
| 8/28/2012 | DSP | Leake | Demoted to reserve roster | | | Before |
| 8/28/2012 | HOL | Bundy | Demoted to reserve roster | | | Before |
| 8/28/2012 | HOL | Duffy | Promoted to active roster | | | Before |
| 8/28/2012 | HOL | Machado | Promoted to active roster | | | Before |
| 8/28/2012 | HOL | McCarthy | Demoted to reserve roster | | | Before |
| 8/28/2012 | HOL | Neshek | Promoted to active roster | | | Before |
| 8/28/2012 | HOL | Rodriguez,P | Demoted to reserve roster | | | Before |
| 8/28/2012 | MAN | Byrd,M | Demoted to reserve roster | | | Before |
| 8/28/2012 | MAN | Collmenter | Demoted to reserve roster | | | Before |
| 8/28/2012 | MAN | Garcia,F | Demoted to reserve roster | | | Before |
| 8/28/2012 | MAN | Hill,R | Promoted to active roster | | | Before |
| 8/28/2012 | MAN | Pryor | Demoted to reserve roster | | | Before |
| 8/28/2012 | MAN | Ramos,C | Promoted to active roster | | | Before |
| 8/28/2012 | MAN | Sappelt | Promoted to active roster | | | Before |
| 8/28/2012 | MAN | Sierra | Activated from disabled list | | | Before |
| 8/28/2012 | PAC | Lowe,M | Demoted to reserve roster | | | Before |
| 8/28/2012 | PAW | Bard | Demoted to reserve roster | | | Before |
| 8/28/2012 | PAW | Dunn,M | Demoted to reserve roster | | | Before |
| 8/28/2012 | PAW | Theriot | Demoted to reserve roster | | | Before |
| 8/28/2012 | PAW | Young,CB | Demoted to reserve roster | | | Before |
| 8/28/2012 | PBC | Crain | Promoted to active roster | | | Before |
| 8/28/2012 | PBC | Kontos | Demoted to reserve roster | | | Before |
| 8/28/2012 | PBC | McKenry | Demoted to reserve roster | | | Before |
| 8/28/2012 | PBC | McKenry | Promoted to active roster | | | Before |
| 8/28/2012 | SFS | Hairston,J | Demoted to reserve roster | | | Before |
| 8/28/2012 | SFS | Millwood | Activated from disabled list | | | Before |
| 8/28/2012 | SFS | Rzepczynski | Demoted to reserve roster | | | Before |
| 8/28/2012 | WCM | Byrdak | Demoted to reserve roster | | | Before |
| 8/28/2012 | WCM | Correia | Promoted to active roster | | | Before |
| 8/28/2012 | WCM | Feldman | Promoted to active roster | | | Before |
| 8/28/2012 | WCM | Laird,G | Demoted to reserve roster | | | Before |
| 8/28/2012 | WCM | Morrow | Activated from disabled list | | | Before |
| 8/28/2012 | WCM | Wallace | Demoted to reserve roster | | | Before |
| 8/28/2012 | WTB | Dotel | Demoted to reserve roster | | | Before |
| 8/28/2012 | WTB | Treanor | Promoted to active roster | | | Before |
| 8/31/2012 | CGS | Lobaton | Demoted to reserve roster | | | Before |
| 8/31/2012 | CGS | Mesoraco | Promoted to active roster | | | Before |
| 8/31/2012 | CRB | League,B | Promoted to active roster | | | Before |
| 8/31/2012 | CRB | Vincent | Demoted to reserve roster | | | Before |
| 8/31/2012 | DEG | Hernandez,R | Demoted to reserve roster | | | Before |
| 8/31/2012 | DEG | Keuchel | Demoted to reserve roster | | | Before |
| 8/31/2012 | DEG | Olivo | Activated from disabled list | | | Before |
| 8/31/2012 | DEG | Oswalt | Demoted to reserve roster | | | Before |
| 8/31/2012 | DEG | Santana,E | Activated from disabled list | | | Before |
| 8/31/2012 | DEG | Sheets | Promoted to active roster | | | Before |
| 8/31/2012 | HOL | Duffy | Demoted to reserve roster | | | Before |
| 8/31/2012 | HOL | Straily | Promoted to active roster | | | Before |
| 8/31/2012 | MAN | Anderson,BF | Promoted to active roster | | | Before |
| 8/31/2012 | MAN | Friedrich | Demoted to reserve roster | | | Before |
| 8/31/2012 | NHP | Gonzalez,Mig | Demoted to reserve roster | | | Before |
| 8/31/2012 | NHP | Harvey | Promoted to active roster | | | Before |
| 8/31/2012 | PBC | Callaspo | Demoted to reserve roster | | | Before |
| 8/31/2012 | PBC | Furbush | Demoted to reserve roster | | | Before |
| 8/31/2012 | PBC | Lindblom,J | Promoted to active roster | | | Before |
| 8/31/2012 | PBC | Masterson | Demoted to reserve roster | | | Before |
| 8/31/2012 | PBC | Niemann | Promoted to active roster | | | Before |
| 8/31/2012 | PBC | Rodriguez,Al | Activated from disabled list | | | Before |
| 8/31/2012 | PEA | Andino | Promoted to active roster | | | Before |
| 8/31/2012 | PEA | Polanco | Demoted to reserve roster | | | Before |
| 8/31/2012 | TOR | Fien | Demoted to reserve roster | | | Before |
| 8/31/2012 | TOR | Locke | Promoted to active roster | | | Before |
| 9/3/2012 | ASB | Downs,S | Demoted to reserve roster | | | Before |
| 9/3/2012 | AUR | Bernadina | Demoted to reserve roster | | | Before |
| 9/3/2012 | AUR | Damon | Promoted to active roster | | | Before |
| 9/3/2012 | AUR | Johnson,S | Activated from disabled list | | | Before |
| 9/3/2012 | AVA | Kinney | Demoted to reserve roster | | | Before |
| 9/3/2012 | AVA | Ondrusek | Promoted to active roster | | | Before |
| 9/3/2012 | BOX | Howard | Demoted to reserve roster | | | Before |
| 9/3/2012 | BOX | Moustakas | Promoted to active roster | | | Before |
| 9/3/2012 | CLE | Martin,Le | Demoted to reserve roster | | | Before |
| 9/3/2012 | CLE | Podsednik | Activated from disabled list | | | Before |
| 9/3/2012 | CRB | De Fratus | Demoted to reserve roster | | | Before |
| 9/3/2012 | CRB | Medlen | Promoted to active roster | | | Before |
| 9/3/2012 | DSP | Adams,Mi | Demoted to reserve roster | | | Before |
| 9/3/2012 | DSP | Drew,S | Demoted to reserve roster | | | Before |
| 9/3/2012 | DSP | Leake | Promoted to active roster | | | Before |
| 9/3/2012 | DSP | Pearce,S | Promoted to active roster | | | Before |
| 9/3/2012 | DUR | Atchison | Demoted to reserve roster | | | Before |
| 9/3/2012 | DUR | Lincoln,B | Promoted to active roster | | | Before |
| 9/3/2012 | MAN | Anderson,BF | Demoted to reserve roster | | | Before |
| 9/3/2012 | MAN | Chatwood | Promoted to active roster | | | Before |
| 9/3/2012 | MAN | Fife | Promoted to active roster | | | Before |
| 9/3/2012 | MAN | Hill,R | Demoted to reserve roster | | | Before |
| 9/3/2012 | MAN | Ramos,C | Demoted to reserve roster | | | Before |
| 9/3/2012 | PAW | Leroux | Promoted to active roster | | | Before |
| 9/3/2012 | PAW | Lucroy | Demoted to reserve roster | | | Before |
| 9/3/2012 | PAW | Miller,A | Promoted to active roster | | | Before |
| 9/3/2012 | PAW | Phelps,C | Promoted to active roster | | | Before |
| 9/3/2012 | PAW | Wells,R | Promoted to active roster | | | Before |
| 9/3/2012 | PBC | Moss | Demoted to reserve roster | | | Before |
| 9/3/2012 | WTB | Hechavarria | Demoted to reserve roster | | | Before |
| 9/6/2012 | BOX | McPherson | Demoted to reserve roster | | | Before |
| 9/6/2012 | BOX | Turner,Ja | Promoted to active roster | | | Before |
| 9/6/2012 | CGS | Ramirez,Er | Promoted to active roster | | | Before |
| 9/6/2012 | CGS | Street | Demoted to reserve roster | | | Before |
| 9/6/2012 | CLE | Eovaldi,N | Demoted to reserve roster | | | Before |
| 9/6/2012 | CLE | Grimm | Promoted to active roster | | | Before |
| 9/6/2012 | CLE | Matsuzaka | Placed on disabled list | | 9/5/2012 | Before |
| 9/6/2012 | CLE | Narveson | Promoted to active roster | | | Before |
| 9/6/2012 | DSP | Drew,S | Promoted to active roster | | | Before |
| 9/6/2012 | DSP | Herrera | Demoted to reserve roster | | | Before |
| 9/6/2012 | DSP | McDonald,Jo | Demoted to reserve roster | | | Before |
| 9/6/2012 | DSP | McDonald,Jo | Promoted to active roster | | | Before |
| 9/6/2012 | DSP | Rodriguez,H | Promoted to active roster | | | Before |
| 9/6/2012 | DSP | Valbuena | Demoted to reserve roster | | | Before |
| 9/6/2012 | DUR | Gomez,M | Demoted to reserve roster | | | Before |
| 9/6/2012 | DUR | Nava | Promoted to active roster | | | Before |
| 9/6/2012 | MAN | Font | Promoted to active roster | | | Before |
| 9/6/2012 | MON | Doubront | Promoted to active roster | | | Before |
| 9/6/2012 | MON | Milone | Placed on disabled list | | 9/6/2012 | Before |
| 9/6/2012 | PAC | Carpenter,DL | Promoted to active roster | | | Before |
| 9/6/2012 | PAC | Grandal | Demoted to reserve roster | | | Before |
| 9/6/2012 | PAC | Torrealba,Y | Promoted to active roster | | | Before |
| 9/9/2012 | AUR | Cuddyer | Demoted to reserve roster | | | Before |
| 9/9/2012 | AUR | Presley | Promoted to active roster | | | Before |
| 9/9/2012 | BOX | Howard | Promoted to active roster | | | Before |
| 9/9/2012 | BOX | Mastroianni | Demoted to reserve roster | | | Before |
| 9/9/2012 | CGS | Longoria | Demoted to reserve roster | | | Before |
| 9/9/2012 | CGS | Reynolds,MA | Promoted to active roster | | | Before |
| 9/9/2012 | CLE | Darnell | Promoted to active roster | | | Before |
| 9/9/2012 | CLE | Ruf | Demoted to reserve roster | | | Before |
| 9/9/2012 | CRB | Griffin | Activated from disabled list | | | Before |
| 9/9/2012 | CRB | League,B | Demoted to reserve roster | | | Before |
| 9/9/2012 | CRB | Rogers,M | Promoted to active roster | | | Before |
| 9/9/2012 | CRB | Strasburg | Placed on disabled list | | 9/7/2012 | Before |
| 9/9/2012 | DUR | Crawford,B | Promoted to active roster | | | Before |
| 9/9/2012 | DUR | Gonzalez,Al | Demoted to reserve roster | | | Before |
| 9/9/2012 | HOL | Beachy | Demoted to reserve roster | | | Before |
| 9/9/2012 | NHP | Gonzalez,Mig | Promoted to active roster | | | Before |
| 9/9/2012 | NHP | Harvey | Demoted to reserve roster | | | Before |
| 9/12/2012 | AUR | Iannetta | Demoted to reserve roster | | | Before |
| 9/12/2012 | AUR | Mathis | Promoted to active roster | | | Before |
| 9/12/2012 | BBK | Iwakuma | Demoted to reserve roster | | | Before |
| 9/12/2012 | BBK | Thornburg | Promoted to active roster | | | Before |
| 9/12/2012 | CGS | Doolittle | Demoted to reserve roster | | | Before |
| 9/12/2012 | CGS | Miller,S | Promoted to active roster | | | Before |
| 9/12/2012 | DEG | Kelly,J | Demoted to reserve roster | | | Before |
| 9/12/2012 | DEG | Keuchel | Promoted to active roster | | | Before |
| 9/12/2012 | MAN | Collmenter | Promoted to active roster | | | Before |
| 9/12/2012 | MAN | Fife | Demoted to reserve roster | | | Before |
| 9/12/2012 | MAN | Font | Demoted to reserve roster | | | Before |
| 9/12/2012 | MAN | Garcia,F | Promoted to active roster | | | Before |
| 9/12/2012 | NHP | Bass | Placed on disabled list | | 9/10/2012 | Before |
| 9/12/2012 | NHP | Beavan | Promoted to active roster | | | Before |
| 9/12/2012 | NHP | Gonzalez,Mig | Demoted to reserve roster | | | Before |
| 9/12/2012 | NHP | Hammel | Demoted to reserve roster | | | Before |
| 9/12/2012 | NHP | Porcello | Promoted to active roster | | | Before |
| 9/12/2012 | NHP | Valdes,R | Promoted to active roster | | | Before |
| 9/12/2012 | PAW | Cardenas | Demoted to reserve roster | | | Before |
| 9/12/2012 | PAW | Danks,JC | Demoted to reserve roster | | | Before |
| 9/12/2012 | PAW | Santana | Demoted to reserve roster | | | Before |
| 9/12/2012 | PAW | Turner,Ju | Demoted to reserve roster | | | Before |
| 9/12/2012 | PBC | Votto | Activated from disabled list | | | Before |
| 9/12/2012 | TOR | Cueto | Demoted to reserve roster | | | Before |
| 9/12/2012 | TOR | Ellis,AJ | Demoted to reserve roster | | | Before |
| 9/12/2012 | TOR | Fien | Promoted to active roster | | | Before |
| 9/12/2012 | TOR | Karstens | Promoted to active roster | | | Before |
| 9/12/2012 | TOR | Lewis,C | Demoted to reserve roster | | | Before |
| 9/12/2012 | TOR | Norris,D | Promoted to active roster | | | Before |
| 9/12/2012 | TOR | Tillman | Demoted to reserve roster | | | Before |
| 9/12/2012 | TOR | Volstad | Promoted to active roster | | | Before |
| 9/12/2012 | WCM | Santiago,H | Demoted to reserve roster | | | Before |
| 9/12/2012 | WCM | Ziegler | Demoted to reserve roster | | | Before |
| 9/15/2012 | AVA | Gomez,J | Promoted to active roster | | | Before |
| 9/15/2012 | AVA | Patton | Demoted to reserve roster | | | Before |
| 9/15/2012 | CAR | Francisco,J | Promoted to active roster | | | Before |
| 9/15/2012 | CAR | Thames,E | Demoted to reserve roster | | | Before |
| 9/15/2012 | CLE | Barton | Demoted to reserve roster | | | Before |
| 9/15/2012 | CLE | Ruf | Promoted to active roster | | | Before |
| 9/15/2012 | CLE | Sanchez,H | Demoted to reserve roster | | | Before |
| 9/15/2012 | CLE | Sanchez,H | Promoted to active roster | | | Before |
| 9/15/2012 | CRB | Avilan | Promoted to active roster | | | Before |
| 9/15/2012 | CRB | Stults,E | Demoted to reserve roster | | | Before |
| 9/15/2012 | DSP | Corbin | Demoted to reserve roster | | | Before |
| 9/15/2012 | DSP | LeBlanc | Promoted to active roster | | | Before |
| 9/15/2012 | NHP | Drabek | Promoted to active roster | | | Before |
| 9/15/2012 | NHP | Valdes,R | Demoted to reserve roster | | | Before |
| 9/15/2012 | WCM | Arencibia | Placed on disabled list | | 8/30/2012 | Before |
| 9/15/2012 | WCM | Baker,Jo | Promoted to active roster | | | Before |
| 9/15/2012 | WCM | Cowgill | Promoted to active roster | | | Before |
| 9/15/2012 | WCM | Simon | Promoted to active roster | | | Before |
| 9/15/2012 | WCM | Thole | Promoted to active roster | | | Before |
| 9/15/2012 | WCM | Watson | Demoted to reserve roster | | | Before |
| 9/15/2012 | WCM | Wise,D | Promoted to active roster | | | Before |
| 9/18/2012 | ASB | Coke | Promoted to active roster | | | Before |
| 9/18/2012 | ASB | Nunez | Promoted to active roster | | | Before |
| 9/18/2012 | AUR | Cashner | Promoted to active roster | | | Before |
| 9/18/2012 | AUR | Chen,W | Demoted to reserve roster | | | Before |
| 9/18/2012 | BOX | Beckett,J | Demoted to reserve roster | | | Before |
| 9/18/2012 | BOX | McPherson | Promoted to active roster | | | Before |
| 9/18/2012 | BOX | Teheran | Promoted to active roster | | | Before |
| 9/18/2012 | BOX | Turner,Ja | Demoted to reserve roster | | | Before |
| 9/18/2012 | CLE | Gearrin | Promoted to active roster | | | Before |
| 9/18/2012 | CLE | Grimm | Demoted to reserve roster | | | Before |
| 9/18/2012 | CLE | Rosenthal | Promoted to active roster | | | Before |
| 9/18/2012 | CLE | Ruf | Demoted to reserve roster | | | Before |
| 9/18/2012 | CRB | Ackley | Promoted to active roster | | | Before |
| 9/18/2012 | CRB | Avilan | Demoted to reserve roster | | | Before |
| 9/18/2012 | CRB | Belisario | Demoted to reserve roster | | | Before |
| 9/18/2012 | CRB | Betemit | Demoted to reserve roster | | | Before |
| 9/18/2012 | CRB | Boesch | Promoted to active roster | | | Before |
| 9/18/2012 | CRB | Braun | Demoted to reserve roster | | | Before |
| 9/18/2012 | CRB | De Fratus | Promoted to active roster | | | Before |
| 9/18/2012 | CRB | De Los Santos | Promoted to active roster | | | Before |
| 9/18/2012 | CRB | Ethier | Demoted to reserve roster | | | Before |
| 9/18/2012 | CRB | Gillaspie | Promoted to active roster | | | Before |
| 9/18/2012 | CRB | Guyer | Promoted to active roster | | | Before |
| 9/18/2012 | CRB | Hunter,RT | Promoted to active roster | | | Before |
| 9/18/2012 | CRB | Johnson,Ji | Demoted to reserve roster | | | Before |
| 9/18/2012 | CRB | League,B | Promoted to active roster | | | Before |
| 9/18/2012 | CRB | Medlen | Demoted to reserve roster | | | Before |
| 9/18/2012 | CRB | Wilhelmsen | Demoted to reserve roster | | | Before |
| 9/18/2012 | CRB | Willingham | Demoted to reserve roster | | | Before |
| 9/18/2012 | CRB | Wilson,Ju | Promoted to active roster | | | Before |
| 9/18/2012 | DSP | Hayes | Promoted to active roster | | | Before |
| 9/18/2012 | DSP | Hellickson | Demoted to reserve roster | | | Before |
| 9/18/2012 | DSP | McDonald,Jo | Promoted to active roster | | | Before |
| 9/18/2012 | DSP | Ross,D | Demoted to reserve roster | | | Before |
| 9/18/2012 | DSP | Valbuena | Promoted to active roster | | | Before |
| 9/18/2012 | DSP | Wood,T | Demoted to reserve roster | | | Before |
| 9/18/2012 | DUR | Kennedy.A | Demoted to reserve roster | | | Before |
| 9/18/2012 | DUR | Ryan | Promoted to active roster | | | Before |
| 9/18/2012 | MAN | Anderson,L | Promoted to active roster | | | Before |
| 9/18/2012 | MAN | Bautista,J | Demoted to reserve roster | | | Before |
| 9/18/2012 | MAN | Byrd,M | Promoted to active roster | | | Before |
| 9/18/2012 | MAN | Coleman,L | Demoted to reserve roster | | | Before |
| 9/18/2012 | MAN | Collmenter | Demoted to reserve roster | | | Before |
| 9/18/2012 | MAN | Friedrich | Promoted to active roster | | | Before |
| 9/18/2012 | MAN | Garcia,F | Demoted to reserve roster | | | Before |
| 9/18/2012 | MAN | Hafner | Demoted to reserve roster | | | Before |
| 9/18/2012 | MAN | Lough | Promoted to active roster | | | Before |
| 9/18/2012 | MAN | Pryor | Promoted to active roster | | | Before |
| 9/18/2012 | MAN | Sappelt | Demoted to reserve roster | | | Before |
| 9/18/2012 | MAN | Vitters | Promoted to active roster | | | Before |
| 9/18/2012 | PBC | Estrada | Demoted to reserve roster | | | Before |
| 9/18/2012 | PBC | Familia | Promoted to active roster | | | Before |
| 9/18/2012 | PBC | Frandsen | Promoted to active roster | | | Before |
| 9/18/2012 | PBC | Votto | Demoted to reserve roster | | | Before |
| 9/18/2012 | SFS | Kemp | Demoted to reserve roster | | | Before |
| 9/18/2012 | WTB | Blackley,T | Demoted to reserve roster | | | Before |
| 9/18/2012 | WTB | Wheeler,R | Demoted to reserve roster | | | Before |
| 2/11/2013 | AUR | Mathis | Acquired via trade | HOL | | After |
| 2/11/2013 | AUR | Revere | Acquired via trade | HOL | | After |
| 2/11/2013 | AUR | Romo | Acquired via trade | HOL | | After |
| 2/11/2013 | AUR | Schneider | Traded away | HOL | | After |
| 2/11/2013 | AUR | Soriano,R | Traded away | HOL | | After |
| 2/11/2013 | AUR | Swisher | Traded away | HOL | | After |
| 2/11/2013 | HOL | Mathis | Traded away | AUR | | After |
| 2/11/2013 | HOL | Revere | Traded away | AUR | | After |
| 2/11/2013 | HOL | Romo | Traded away | AUR | | After |
| 2/11/2013 | HOL | Schneider | Acquired via trade | AUR | | After |
| 2/11/2013 | HOL | Soriano,R | Acquired via trade | AUR | | After |
| 2/11/2013 | HOL | Swisher | Acquired via trade | AUR | | After |
| 2/26/2013 | CLE | Carter | Acquired via trade | DUR | | After |
| 2/26/2013 | CLE | Dirks | Traded away | DUR | | After |
| 2/26/2013 | CLE | Hochevar | Acquired via trade | DUR | | After |
| 2/26/2013 | CLE | Hudson,O | Acquired via trade | DUR | | After |
| 2/26/2013 | CLE | Mayberry | Acquired via trade | DUR | | After |
| 2/26/2013 | CLE | Vogelsong | Traded away | DUR | | After |
| 2/26/2013 | DUR | Carter | Traded away | CLE | | After |
| 2/26/2013 | DUR | Dirks | Acquired via trade | CLE | | After |
| 2/26/2013 | DUR | Hochevar | Traded away | CLE | | After |
| 2/26/2013 | DUR | Hudson,O | Traded away | CLE | | After |
| 2/26/2013 | DUR | Mayberry | Traded away | CLE | | After |
| 2/26/2013 | DUR | Vogelsong | Acquired via trade | CLE | | After |
| 2/26/2013 | PEA | Bourn | Traded away | WTB | | After |
| 2/26/2013 | PEA | Kubel | Acquired via trade | WTB | | After |
| 2/26/2013 | PEA | Melancon | Acquired via trade | WTB | | After |
| 2/26/2013 | PEA | Werth | Acquired via trade | WTB | | After |
| 2/26/2013 | WTB | Bourn | Acquired via trade | PEA | | After |
| 2/26/2013 | WTB | Kubel | Traded away | PEA | | After |
| 2/26/2013 | WTB | Melancon | Traded away | PEA | | After |
| 2/26/2013 | WTB | Werth | Traded away | PEA | | After |