| Transactions | ||||||
| Date | Team | Player | Type | OthTm | EffDate | When |
| 4/16/1991 | BON | Anderson | Demoted to reserve roster | Before | ||
| 4/16/1991 | BON | Borders | Demoted to reserve roster | Before | ||
| 4/16/1991 | BON | Browne | Demoted to reserve roster | Before | ||
| 4/16/1991 | BON | Fermin | Demoted to reserve roster | Before | ||
| 4/16/1991 | BON | Guthrie | Demoted to reserve roster | Before | ||
| 4/16/1991 | BON | Sosa | Demoted to reserve roster | Before | ||
| 4/16/1991 | CCL | Burkett | Demoted to reserve roster | Before | ||
| 4/16/1991 | CCL | Caminiti | Demoted to reserve roster | Before | ||
| 4/16/1991 | CCL | Gilkey | Demoted to reserve roster | Before | ||
| 4/16/1991 | EDG | Bichette | Demoted to reserve roster | Before | ||
| 4/16/1991 | EDG | Sheffield | Demoted to reserve roster | Before | ||
| 4/16/1991 | EDG | Viola | Demoted to reserve roster | Before | ||
| 4/16/1991 | MUL | Hayes,C | Demoted to reserve roster | Before | ||
| 4/22/1991 | MUL | Avery | Promoted to active roster | Before | ||
| 4/22/1991 | MUL | Myers | Demoted to reserve roster | Before | ||
| 5/15/1991 | EDG | Gray | Traded away | LON | After | |
| 5/15/1991 | EDG | Lilliquist | Acquired via trade | LON | After | |
| 5/15/1991 | LON | Gray | Acquired via trade | EDG | After | |
| 5/15/1991 | LON | Lilliquist | Traded away | EDG | After | |
| 5/16/1991 | EDG | Viola | Promoted to active roster | Before | ||
| 5/22/1991 | LON | Slocumb | Demoted to reserve roster | Before | ||
| 5/27/1991 | BT | Puckett | Acquired via trade | OTR | After | |
| 5/27/1991 | BT | Rasmussen | Acquired via trade | OTR | After | |
| 5/27/1991 | BT | Ryan | Traded away | OTR | After | |
| 5/27/1991 | OTR | Puckett | Traded away | BT | After | |
| 5/27/1991 | OTR | Rasmussen | Traded away | BT | After | |
| 5/27/1991 | OTR | Ryan | Acquired via trade | BT | After | |
| 6/2/1991 | MAD | Andersen | Traded away | OTR | After | |
| 6/2/1991 | MAD | Bankhead | Acquired via trade | OTR | After | |
| 6/2/1991 | OTR | Andersen | Acquired via trade | MAD | After | |
| 6/2/1991 | OTR | Bankhead | Traded away | MAD | After | |
| 7/20/1991 | COP | Hough | Acquired via trade | CRH | After | |
| 7/20/1991 | COP | Leiter | Traded away | CRH | After | |
| 7/20/1991 | CRH | Hough | Traded away | COP | After | |
| 7/20/1991 | CRH | Leiter | Acquired via trade | COP | After | |
| 7/20/1991 | GEO | Belcher | Acquired via trade | MAD | After | |
| 7/20/1991 | GEO | Greenwell | Traded away | MAD | After | |
| 7/20/1991 | MAD | Belcher | Traded away | GEO | After | |
| 7/20/1991 | MAD | Greenwell | Acquired via trade | GEO | After | |
| 7/21/1991 | COP | Plesac | Demoted to reserve roster | Before | ||
| 7/21/1991 | GEO | Ojeda | Demoted to reserve roster | Before | ||
| 7/26/1991 | MAD | Holman | Acquired via trade | Pal | After | |
| 7/26/1991 | MAD | Wallach | Acquired via trade | Pal | After | |
| 7/26/1991 | MAD | Whitehurst | Traded away | Pal | After | |
| 7/26/1991 | Pal | Holman | Traded away | MAD | After | |
| 7/26/1991 | Pal | Wallach | Traded away | MAD | After | |
| 7/26/1991 | Pal | Whitehurst | Acquired via trade | MAD | After | |
| 7/27/1991 | WIZ | Leary | Demoted to reserve roster | Before | ||
| 10/12/1991 | COP | McDonald | Demoted to reserve roster | Before | ||
| 10/12/1991 | GEO | Candiotti | Demoted to reserve roster | Before | ||
| 10/12/1991 | LON | Cone | Demoted to reserve roster | Before | ||