Marlins Roster & Staff
Transactions
| Date | Transaction |
| 07/31/18 | Miami Marlins optioned RHP Ben Meyer to New Orleans Baby Cakes. |
| 07/31/18 | Miami Marlins traded RHP Brad Ziegler to Arizona Diamondbacks for RHP Tommy Eveld. |
| 07/31/18 | Miami Marlins traded RHP Brad Ziegler to Arizona Diamondbacks for RHP Tommy Eveld. |
| 07/31/18 | Miami Marlins traded LF Cameron Maybin to Seattle Mariners for SS Bryson Brigman and Future Considerations. |
| 07/31/18 | Miami Marlins traded LF Cameron Maybin to Seattle Mariners for SS Bryson Brigman and Future Considerations. |
| 07/31/18 | Miami Marlins selected the contract of RF Isaac Galloway from New Orleans Baby Cakes. |
| 07/31/18 | Miami Marlins recalled LHP Jarlin Garcia from New Orleans Baby Cakes. |
| 07/31/18 | Miami Marlins activated RHP Tayron Guerrero from the 10-day injured list. |
| 07/26/18 | Miami Marlins signed free agent RHP Jeremias Vasquez to a minor league contract. |
| 07/24/18 | Miami Marlins recalled Magneuris Sierra from New Orleans Baby Cakes. |
| 07/24/18 | Miami Marlins placed LF Garrett Cooper on the 10-day disabled list retroactive to July 21, 2018. Right wrist sprain. |
| 07/23/18 | Miami Marlins sent RHP Sandy Alcantara on a rehab assignment to Jupiter Hammerheads. |
| 07/21/18 | Miami Marlins sent RHP Tayron Guerrero on a rehab assignment to Jacksonville Jumbo Shrimp. |
| 07/12/18 | Miami Marlins optioned C Chad Wallach to New Orleans Baby Cakes. |
| 07/12/18 | Miami Marlins activated C J.T. Realmuto from the paternity list. |
| 07/09/18 | Miami Marlins selected the contract of RHP Javy Guerra from New Orleans Baby Cakes. |
| 07/09/18 | Miami Marlins placed C J.T. Realmuto on the paternity list. |
| 07/09/18 | Miami Marlins transferred LHP Caleb Smith from the 10-day disabled list to the 60-day disabled list. Left shoulder tightness. |
| 07/09/18 | Miami Marlins placed RHP Drew Rucinski on the 10-day disabled list. Right groin strain. |
| 07/09/18 | Miami Marlins recalled Chad Wallach from New Orleans Baby Cakes. |
| 07/07/18 | Miami Marlins sent LF JB Shuck outright to New Orleans Baby Cakes. |
| 07/06/18 | Miami Marlins signed LHP Andrew Miller. |
| 07/06/18 | Miami Marlins activated RF Garrett Cooper from the 60-day disabled list. |
| 07/06/18 | Miami Marlins optioned LHP Dillon Peters to New Orleans Baby Cakes. |
| 07/06/18 | Miami Marlins signed free agent RHP Breidy Encarnacion to a minor league contract. |
| 07/05/18 | Miami Marlins activated 3B Martin Prado from the 10-day disabled list. |
| 07/05/18 | Miami Marlins recalled Ben Meyer from New Orleans Baby Cakes. |
| 07/05/18 | Miami Marlins placed RHP Tayron Guerrero on the 10-day disabled list retroactive to July 4, 2018. Left lumbar strain. |
| 07/05/18 | Miami Marlins designated RF JB Shuck for assignment. |
| 07/05/18 | Miami Marlins signed free agent LHP Maycold Leon to a minor league contract. |
| 07/04/18 | Miami Marlins activated RHP Jose Urena from the 10-day disabled list. |
| 07/04/18 | Miami Marlins placed CF Lewis Brinson on the 10-day disabled list. Right hip inflammation. |
| 07/04/18 | Miami Marlins recalled Dillon Peters from New Orleans Baby Cakes. |
| 07/03/18 | Sandy Alcantara roster status changed by Miami Marlins. |
| 07/02/18 | Miami Marlins signed free agent RHP Luis Lopez to a minor league contract. |
| 07/02/18 | Miami Marlins signed free agent SS Isaac De Leon to a minor league contract. |
| 07/02/18 | Miami Marlins signed free agent RHP Jorge Mercedes to a minor league contract. |
| 07/02/18 | Miami Marlins signed free agent C Ene Leon to a minor league contract. |
| 07/02/18 | Miami Marlins signed free agent SS Raul Campos to a minor league contract. |
| 07/02/18 | Miami Marlins signed free agent LHP Erick Carrasco to a minor league contract. |
| 07/02/18 | Miami Marlins signed free agent CF Yoelvis Sanchez to a minor league contract. |
| 07/02/18 | Miami Marlins signed free agent SS Cristhian Rodriguez to a minor league contract. |
| 07/02/18 | Miami Marlins signed free agent CF Jhonny Melenciano to a minor league contract. |
| 07/01/18 | Miami Marlins activated RHP Dan Straily. |