Marlins Roster & Staff
Transactions
| Date | Transaction |
| 05/09/21 | Miami Marlins optioned LHP Daniel Castano to Jacksonville Jumbo Shrimp. |
| 05/09/21 | Miami Marlins selected the contract of RHP Luis Madero from Jacksonville Jumbo Shrimp. |
| 05/09/21 | Miami Marlins placed RHP Jorge Guzman on the 60-day injured list. Right elbow spur. |
| 05/08/21 | Miami Marlins recalled LHP Daniel Castano from Jacksonville Jumbo Shrimp. |
| 05/08/21 | Miami Marlins optioned SS Jose Devers to Jacksonville Jumbo Shrimp. |
| 05/08/21 | Miami Marlins signed free agent 2B Nick Lovullo to a minor league contract. |
| 05/08/21 | Miami Marlins signed free agent 3B Deven Marrero to a minor league contract. |
| 05/04/21 | Miami Marlins activated 3B Brian Anderson from the 10-day injured list. |
| 05/04/21 | Miami Marlins selected the contract of LHP Rob Zastryzny from Long Island Ducks. |
| 05/04/21 | Miami Marlins optioned CF Monte Harrison to Jacksonville Jumbo Shrimp. |
| 05/04/21 | Miami Marlins selected the contract of RHP Anthony Bender from Marlins Alternate Training Site. |
| 05/03/21 | Miami Marlins signed free agent SS Ricky Aracena to a minor league contract. |
| 05/03/21 | RHP Paul Campbell roster status changed by Miami Marlins. |
