Roster y Personal de los Red Sox
Red Sox
| Fecha | Transacción |
| 06/22/21 | Boston Red Sox recalled C Connor Wong from Worcester Red Sox. |
| 06/22/21 | Boston Red Sox placed C Kevin Plawecki on the 10-day injured list. Left hamstring strain. |
| 06/16/21 | Milwaukee Brewers claimed RHP Ryan Weber off waivers from Boston Red Sox. |
| 06/16/21 | Boston Red Sox sent RHP Brandon Brennan outright to Worcester Red Sox. |
| 06/16/21 | Boston Red Sox optioned 2B Michael Chavis to Worcester Red Sox. |
| 06/16/21 | Boston Red Sox activated RHP Yacksel Rios. |
| 06/14/21 | Boston Red Sox designated RHP Ryan Weber for assignment. |
| 06/14/21 | Boston Red Sox recalled 2B Michael Chavis from Worcester Red Sox. |
| 06/14/21 | Seattle Mariners traded RHP Yacksel Rios to Boston Red Sox for cash. |
| 06/13/21 | Boston Red Sox designated RHP Brandon Brennan for assignment. |
| 06/13/21 | Boston Red Sox selected the contract of RHP Ryan Weber from Worcester Red Sox. |
| 06/10/21 | Boston Red Sox optioned RHP Phillips Valdez to Worcester Red Sox. |
| 06/10/21 | Boston Red Sox recalled RHP Brandon Brennan from Worcester Red Sox. |
| 06/07/21 | Boston Red Sox sent RHP Colten Brewer outright to Worcester Red Sox. |
| 06/04/21 | Kansas City Royals traded RHP Grant Gambrell and RHP Luis De La Rosa to Boston Red Sox. |
| 06/04/21 | Kansas City Royals traded RHP Grant Gambrell and RHP Luis De La Rosa to Boston Red Sox. |
| 06/04/21 | New York Mets traded RF Freddy Valdez to Boston Red Sox. |
| 06/03/21 | Boston Red Sox designated RHP Colten Brewer for assignment. |
| 06/03/21 | Boston Red Sox selected the contract of RHP Brandon Workman from Worcester Red Sox. |
| 06/03/21 | Boston Red Sox optioned RHP Colten Brewer to Worcester Red Sox. |
