Marlins Roster & Staff
Transactions
| Date | Transaction |
| 09/29/21 | Miami Marlins optioned LHP Daniel Castano to Jacksonville Jumbo Shrimp. |
| 09/28/21 | Miami Marlins recalled LHP Daniel Castano from Jacksonville Jumbo Shrimp. |
| 09/26/21 | Miami Marlins sent RHP Taylor Williams outright to Jacksonville Jumbo Shrimp. |
| 09/23/21 | Miami Marlins sent RHP Pablo Lopez on a rehab assignment to Jacksonville Jumbo Shrimp. |
| 09/22/21 | Miami Marlins selected the contract of RHP Luis Madero from Jacksonville Jumbo Shrimp. |
| 09/22/21 | Miami Marlins designated RHP Taylor Williams for assignment. |
| 09/17/21 | Miami Marlins activated C Payton Henry. |
| 09/17/21 | Miami Marlins activated C Payton Henry. |
| 09/17/21 | Miami Marlins selected the contract of C Payton Henry from Jacksonville Jumbo Shrimp. |
| 09/17/21 | Miami Marlins placed RHP Pablo Lopez on the 60-day injured list. |
| 09/17/21 | Miami Marlins optioned SS Isan Diaz to Jacksonville Jumbo Shrimp. |
| 09/17/21 | Miami Marlins selected the contract of C Nick Fortes from Jacksonville Jumbo Shrimp. |
| 09/17/21 | Miami Marlins placed 3B Brian Anderson on the 60-day injured list. Left shoulder subluxation. |
| 09/17/21 | Miami Marlins placed C Jorge Alfaro on the 10-day injured list. Left calf strain. |
| 09/11/21 | Miami Marlins released LHP Ross Detwiler. |
| 09/09/21 | Miami Marlins sent 3B Deven Marrero outright to Jacksonville Jumbo Shrimp. |
| 09/08/21 | Miami Marlins placed 1B Jesus Aguilar on the 10-day injured list. |
| 09/08/21 | Miami Marlins recalled 1B Lewin Diaz from Jacksonville Jumbo Shrimp. |
| 09/07/21 | Miami Marlins selected the contract of SS Eddy Alvarez from Jacksonville Jumbo Shrimp. |
| 09/07/21 | Miami Marlins activated RHP Taylor Williams. |
| 09/07/21 | Miami Marlins designated LHP Ross Detwiler for assignment. |
| 09/06/21 | Miami Marlins claimed RHP Taylor Williams off waivers from San Diego Padres. |
| 09/06/21 | Miami Marlins designated 3B Deven Marrero for assignment. |
| 09/05/21 | Miami Marlins sent RHP Austin Pruitt outright to Jacksonville Jumbo Shrimp. |
| 09/03/21 | Miami Marlins selected the contract of 3B Deven Marrero from Jacksonville Jumbo Shrimp. |
| 09/03/21 | Miami Marlins placed 3B Brian Anderson on the 10-day injured list. Left shoulder subluxation. |
| 09/03/21 | Miami Marlins placed RHP Jorge Guzman on the 60-day injured list. Right elbow soreness. |
| 09/02/21 | Miami Marlins activated RHP Paul Campbell from the 10-day injured list. |
| 09/02/21 | Miami Marlins designated RHP Austin Pruitt for assignment. |
| 09/01/21 | Miami Marlins activated LHP Trevor Rogers. |
| 09/01/21 | 1B Lewin Diaz returned to Jacksonville Jumbo Shrimp from Miami Marlins. |
| 09/01/21 | Miami Marlins activated 2B Joe Panik from the 10-day injured list. |