| 1/6/20 |
Miami Marlins traded RHP Kyle Keller to Los Angeles Angels for C Jose Estrada. |
| 1/7/20 |
Miami Marlins designated RHP Austin Brice for assignment. |
| 1/7/20 |
Miami Marlins signed free agent OF Corey Dickerson. |
| 1/9/20 |
Miami Marlins designated LF Austin Dean for assignment. |
| 1/9/20 |
Miami Marlins signed free agent C Francisco Cervelli. |
| 1/10/20 |
Miami Marlins traded RHP Austin Brice to Boston Red Sox for 2B Angeudis Santos. |
| 1/14/20 |
Miami Marlins traded LF Austin Dean to St. Louis Cardinals for RF Diowill Burgos. |
| 1/15/20 |
Miami Marlins designated LHP Brian Moran for assignment. |
| 1/15/20 |
New York Yankees traded LHP Stephen Tarpley to Miami Marlins for cash and 3B James Nelson. |
| 1/17/20 |
Miami Marlins released LHP Brian Moran. |