Marlins Roster & Staff
Transactions
| Date | Transaction |
| 07/31/21 | Miami Marlins signed LHP Justin Fall. |
| 07/31/21 | Miami Marlins activated C Alex Jackson. |
| 07/31/21 | Miami Marlins optioned RHP Jordan Holloway to Jacksonville Jumbo Shrimp. |
| 07/31/21 | Miami Marlins activated LHP Trevor Rogers from the 10-day injured list. |
| 07/31/21 | Miami Marlins sent RHP Elieser Hernandez on a rehab assignment to Pensacola Blue Wahoos. |
| 07/31/21 | Miami Marlins designated RHP Preston Guilmet for assignment. |
| 07/30/21 | Miami Marlins signed SS Bennett Hostetler. |
| 07/30/21 | Miami Marlins traded LF Adam Duvall to Atlanta Braves for C Alex Jackson. |
| 07/30/21 | Miami Marlins traded LF Adam Duvall to Atlanta Braves for C Alex Jackson. |
| 07/30/21 | Miami Marlins traded RHP John Curtiss to Milwaukee Brewers for C Payton Henry. |
| 07/30/21 | Miami Marlins traded RHP John Curtiss to Milwaukee Brewers for C Payton Henry. |
| 07/30/21 | Miami Marlins designated CF Corey Bird for assignment. |
| 07/30/21 | Miami Marlins designated 3B Deven Marrero for assignment. |
| 07/30/21 | Miami Marlins selected the contract of RF Bryan De La Cruz from Jacksonville Jumbo Shrimp. |
| 07/30/21 | Miami Marlins signed LHP Chandler Jozwiak. |
| 07/30/21 | Los Angeles Dodgers claimed C Chad Wallach off waivers from Miami Marlins. |
| 07/30/21 | Miami Marlins selected the contract of OF Brian Miller from Jacksonville Jumbo Shrimp. |
| 07/30/21 | Miami Marlins activated SS Jazz Chisholm Jr. from the 10-day injured list. |
| 07/30/21 | Miami Marlins activated RHP Austin Pruitt. |
| 07/29/21 | Miami Marlins signed free agent RHP Bryan Mitchell to a minor league contract. |
| 07/29/21 | Miami Marlins signed LHP Caleb Wurster. |
| 07/29/21 | Miami Marlins signed free agent LHP Jared Pettitte to a minor league contract. |
| 07/29/21 | Miami Marlins signed RHP Hunter Perdue. |
| 07/29/21 | Miami Marlins optioned LHP Jesus Luzardo to Jacksonville Jumbo Shrimp. |
| 07/28/21 | RHP Zack Leban roster status changed by Miami Marlins. |
| 07/28/21 | Miami Marlins signed 1B Zach Zubia. |
| 07/28/21 | Miami Marlins signed OF Tanner Allen. |
| 07/28/21 | Houston Astros traded RF Bryan De La Cruz and RHP Austin Pruitt to Miami Marlins for RHP Yimi Garcia. |
| 07/28/21 | Houston Astros traded RF Bryan De La Cruz and RHP Austin Pruitt to Miami Marlins for RHP Yimi Garcia. |
| 07/28/21 | Houston Astros traded RF Bryan De La Cruz and RHP Austin Pruitt to Miami Marlins for RHP Yimi Garcia. |
| 07/28/21 | Miami Marlins traded LF Starling Marte to Oakland Athletics for LHP Jesus Luzardo. |
| 07/28/21 | Miami Marlins selected the contract of CF Corey Bird from Jacksonville Jumbo Shrimp. |
| 07/28/21 | Miami Marlins traded LF Starling Marte to Oakland Athletics for LHP Jesus Luzardo. |
| 07/28/21 | Miami Marlins selected the contract of RHP Preston Guilmet from Jacksonville Jumbo Shrimp. |
| 07/28/21 | Miami Marlins sent RHP Luis Madero outright to Jacksonville Jumbo Shrimp. |
| 07/28/21 | Miami Marlins placed 1B Garrett Cooper on the 60-day injured list. Left elbow sprain. |
| 07/27/21 | Miami Marlins designated RHP Luis Madero for assignment. |
| 07/27/21 | Miami Marlins recalled 1B Lewin Diaz from Jacksonville Jumbo Shrimp. |
| 07/26/21 | Miami Marlins sent RHP Andrew Bellatti outright to Jacksonville Jumbo Shrimp. |
| 07/25/21 | Miami Marlins optioned LHP Braxton Garrett to Jacksonville Jumbo Shrimp. |
| 07/25/21 | Miami Marlins activated RHP Sandy Alcantara from the bereavement list. |
| 07/24/21 | Miami Marlins signed free agent RF Kyler Castillo to a minor league contract. |
| 07/24/21 | Miami Marlins signed RHP Brandon White. |
| 07/24/21 | Miami Marlins recalled LHP Braxton Garrett from Jacksonville Jumbo Shrimp. |
| 07/24/21 | Miami Marlins signed free agent C Paul McIntosh to a minor league contract. |
| 07/24/21 | Miami Marlins activated 3B Brian Anderson. |
| 07/24/21 | Miami Marlins placed LHP Trevor Rogers on the 10-day injured list. Right lower back muscle spasm. |
| 07/24/21 | Miami Marlins designated C Chad Wallach for assignment. |
| 07/23/21 | Miami Marlins signed C Joe Mack. |
| 07/23/21 | Miami Marlins designated RHP Andrew Bellatti for assignment. |
| 07/23/21 | Miami Marlins selected the contract of 3B Deven Marrero from Jacksonville Jumbo Shrimp. |
| 07/23/21 | Miami Marlins recalled C Chad Wallach from Jacksonville Jumbo Shrimp. |
| 07/23/21 | Miami Marlins placed 2B Jon Berti on the 7-day injured list. Concussion. |
| 07/22/21 | Miami Marlins recalled RHP Jordan Holloway from Jacksonville Jumbo Shrimp. |
| 07/22/21 | Miami Marlins signed RHP Jesse Bergin. |
| 07/22/21 | Miami Marlins optioned RHP Nick Neidert to Jacksonville Jumbo Shrimp. |
| 07/22/21 | Miami Marlins signed SS Jordan McCants. |
| 07/21/21 | Miami Marlins optioned CF Monte Harrison to Jacksonville Jumbo Shrimp. |
| 07/21/21 | Miami Marlins recalled RHP Nick Neidert from Jacksonville Jumbo Shrimp. |
| 07/20/21 | Miami Marlins placed SS Jose Devers on the 60-day injured list. Right shoulder impingement. |
| 07/20/21 | Miami Marlins selected the contract of RHP Luis Madero from Jacksonville Jumbo Shrimp. |
| 07/20/21 | Miami Marlins placed RHP Sandy Alcantara on the bereavement list. |
| 07/20/21 | Miami Marlins signed free agent RHP Matt Pobereyko to a minor league contract. |
| 07/19/21 | Miami Marlins optioned LHP Braxton Garrett to Jacksonville Jumbo Shrimp. |
| 07/19/21 | Miami Marlins placed SS Jazz Chisholm Jr. on the 10-day injured list. Left shoulder contusion. |
| 07/19/21 | Miami Marlins selected the contract of RHP Andrew Bellatti from Jacksonville Jumbo Shrimp. |
| 07/19/21 | Miami Marlins placed 1B Garrett Cooper on the 10-day injured list. Left elbow sprain. |
| 07/19/21 | Miami Marlins recalled CF Lewis Brinson from Jacksonville Jumbo Shrimp. |
| 07/18/21 | Miami Marlins signed RHP Gabe Bierman. |
| 07/18/21 | Miami Marlins signed LHP Pat Monteverde. |
| 07/18/21 | Miami Marlins signed RHP Jake Schrand. |
| 07/18/21 | Miami Marlins recalled LHP Braxton Garrett from Jacksonville Jumbo Shrimp. |
| 07/18/21 | Miami Marlins signed free agent OF Brady Allen to a minor league contract. |
| 07/17/21 | Miami Marlins signed free agent RHP Cody Mincey to a minor league contract. |
| 07/17/21 | Miami Marlins activated RHP John Curtiss. |
| 07/17/21 | Miami Marlins optioned RHP Jordan Holloway to Jacksonville Jumbo Shrimp. |
| 07/17/21 | Miami Marlins signed free agent RHP Troy Cruz to a minor league contract. |
| 07/17/21 | Miami Marlins placed RHP Pablo Lopez on the 10-day injured list. Right rotator cuff strain. |
| 07/16/21 | Miami Marlins placed CF Jesus Sanchez on the 10-day injured list. |
| 07/16/21 | Miami Marlins recalled SS Isan Diaz from Jacksonville Jumbo Shrimp. |
| 07/16/21 | Miami Marlins recalled RHP Jordan Holloway from Jacksonville Jumbo Shrimp. |
| 07/16/21 | Miami Marlins recalled SS Isan Diaz. |
| 07/16/21 | Miami Marlins sent 3B Brian Anderson on a rehab assignment to Jacksonville Jumbo Shrimp. |
| 07/16/21 | Miami Marlins recalled SS Isan Diaz. |
| 07/15/21 | Miami Marlins signed free agent LHP Erik Cha to a minor league contract. |
| 07/15/21 | Miami Marlins signed free agent RHP Eddy Tavarez to a minor league contract. |
| 07/13/21 | Miami Marlins sent LHP Shawn Morimando outright to Jacksonville Jumbo Shrimp. |
| 07/13/21 | Miami Marlins signed free agent 3B Kole Enright to a minor league contract. |
| 07/13/21 | Miami Marlins sent RHP John Curtiss on a rehab assignment to Beloit Snappers. |
| 07/13/21 | Miami Marlins optioned RHP Jorge Guzman to Jacksonville Jumbo Shrimp. |
| 07/13/21 | Miami Marlins sent RHP Preston Guilmet outright to Jacksonville Jumbo Shrimp. |
| 07/11/21 | Miami Marlins designated RHP Preston Guilmet for assignment. |
| 07/11/21 | Miami Marlins recalled CF Monte Harrison from Jacksonville Jumbo Shrimp. |
| 07/10/21 | Miami Marlins designated LHP Shawn Morimando for assignment. |
| 07/10/21 | Miami Marlins selected the contract of RHP Preston Guilmet from Jacksonville Jumbo Shrimp. |
| 07/09/21 | Miami Marlins optioned RHP Nick Neidert to Jacksonville Jumbo Shrimp. |
| 07/09/21 | Miami Marlins selected the contract of LHP Shawn Morimando from Jacksonville Jumbo Shrimp. |
| 07/09/21 | Miami Marlins placed LHP Daniel Castano on the 60-day injured list. Left shoulder impingement. |
| 07/08/21 | Miami Marlins recalled RHP Nick Neidert from Jacksonville Jumbo Shrimp. |
| 07/08/21 | Miami Marlins optioned RHP Jordan Holloway to Jacksonville Jumbo Shrimp. |
| 07/04/21 | Miami Marlins recalled RHP Jordan Holloway from Jacksonville Jumbo Shrimp. |
| 07/04/21 | Miami Marlins placed RHP John Curtiss on the 10-day injured list. Neck stiffness. |
| 07/03/21 | Tampa Bay Rays traded RHP David Hess to Miami Marlins for RHP Justin Sterner and cash. |
| 07/03/21 | Miami Marlins optioned RHP Jordan Holloway to Jacksonville Jumbo Shrimp. |
| 07/03/21 | Miami Marlins selected the contract of RHP David Hess from Jacksonville Jumbo Shrimp. |
| 07/03/21 | Miami Marlins sent SS Jose Devers on a rehab assignment to Jacksonville Jumbo Shrimp. |
| 07/03/21 | Tampa Bay Rays traded RHP David Hess to Miami Marlins for RHP Justin Sterner and cash. |
| 07/02/21 | Miami Marlins sent SS Luis Marte outright to Jacksonville Jumbo Shrimp. |