| Date | Player | Position | Transaction |
|---|---|---|---|
| May 21 | Jared Hughes | RP | Sent to Minors by Pittsburgh |
| May 21 | José Contreras | RP | Reinstated from Bereavement/Family Medical Emergency List by Pittsburgh |
| May 17 | Jared Hughes | RP | Called Up from Minors by Pittsburgh |
| May 17 | Brian Jeroloman | C | Traded from Pittsburgh to Washington (for cash considerations) |
| May 17 | José Contreras | RP | Placed on Bereavement/Family Medical Emergency List by Pittsburgh |
| May 16 | Charlie Morton | SP | Sent to Minors for Rehabilitation by Pittsburgh |
| May 16 | Chase d'Arnaud | SS/2B | Sent to Minors for Rehabilitation by Pittsburgh |
| May 15 | Jordy Mercer | SS/2B | Called Up from Minors by Pittsburgh |
| May 13 | Jordy Mercer | SS/2B | Sent to Minors by Pittsburgh |
| May 13 | Jeff Karstens | SP | Sent to Minors for Rehabilitation by Pittsburgh |
| May 13 | Neil Walker | 2B/3B | Recalled From Minors Rehab by Pittsburgh |
| May 11 | Duke Welker | RP | Sent to Minors by Pittsburgh |
| May 11 | Francisco Liriano | SP | Recalled From Minors Rehab by Pittsburgh |
| May 10 | Jonathan Sánchez | SP | Cleared Waivers and Became a Free Agent by Pittsburgh |
| May 9 | Neil Walker | 2B/3B | Sent to Minors for Rehabilitation by Pittsburgh |
| May 8 | Jonathan Sánchez | SP | Released by Pittsburgh |
| May 8 | Josh Harrison | SS/3B | Sent to Minors by Pittsburgh |
| May 8 | Duke Welker | RP | Called Up from Minors by Pittsburgh |
| May 7 | Josh Harrison | SS/3B | Called Up from Minors by Pittsburgh |
| May 4 | Charlie Morton | SP | Recalled From Minors Rehab by Pittsburgh |
| May 3 | Jared Hughes | RP | Sent to Minors by Pittsburgh |
| May 3 | Jordy Mercer | SS/2B | Called Up from Minors by Pittsburgh |
| May 3 | José Contreras | RP | Purchased From Minors by Pittsburgh |