Cardinals Roster & Staff
Cardinals
| Date | Transaction |
| 07/22/21 | St. Louis Cardinals sent RHP Daniel Ponce de Leon on a rehab assignment to Memphis Redbirds. |
| 07/22/21 | St. Louis Cardinals signed RHP Andre Granillo. |
| 07/22/21 | St. Louis Cardinals signed RHP Austin Love. |
| 07/22/21 | St. Louis Cardinals signed LHP Chris Gerard. |
| 07/22/21 | St. Louis Cardinals signed LHP Hayes Heinecke. |
| 07/22/21 | St. Louis Cardinals signed SS Mack Chambers. |
| 07/22/21 | St. Louis Cardinals signed free agent RHP Ryan Loutos to a minor league contract. |
| 07/22/21 | St. Louis Cardinals signed free agent 3B Noah Mendlinger to a minor league contract. |
| 07/22/21 | St. Louis Cardinals signed free agent C Wade Stauss to a minor league contract. |
| 07/22/21 | St. Louis Cardinals signed OF Ryan Holgate. |
| 07/22/21 | St. Louis Cardinals signed free agent RHP Bryan Pope to a minor league contract. |
| 07/21/21 | New York Mets claimed RHP Roel Ramirez off waivers from St. Louis Cardinals. |
| 07/20/21 | St. Louis Cardinals recalled RHP Johan Oviedo from Memphis Redbirds. |
| 07/20/21 | St. Louis Cardinals optioned RHP Junior Fernandez to Memphis Redbirds. |
| 07/19/21 | St. Louis Cardinals optioned LF Lars Nootbaar to Memphis Redbirds. |
| 07/19/21 | St. Louis Cardinals signed 1B Thomas Francisco. |
| 07/19/21 | St. Louis Cardinals signed RHP Gordon Graceffo. |
| 07/19/21 | St. Louis Cardinals recalled RHP Jake Woodford from Memphis Redbirds. |
| 07/19/21 | St. Louis Cardinals signed LHP Alex Cornwell. |
| 07/19/21 | St. Louis Cardinals signed C Aaron McKeithan. |
| 07/19/21 | St. Louis Cardinals signed RHP Andrew Marrero. |
| 07/19/21 | St. Louis Cardinals signed RHP Zane Mills. |
| 07/16/21 | St. Louis Cardinals signed RHP Michael McGreevy. |
| 07/16/21 | St. Louis Cardinals selected the contract of LHP T.J. McFarland from Memphis Redbirds. |
| 07/15/21 | St. Louis Cardinals optioned LHP Brandon Waddell to Memphis Redbirds. |
| 07/15/21 | St. Louis Cardinals signed RHP Trent Baker. |
| 07/12/21 | St. Louis Cardinals signed free agent 3B Osvaldo Tovalin to a minor league contract. |
| 07/12/21 | St. Louis Cardinals signed OF Mike Antico. |
| 07/12/21 | St. Louis Cardinals signed LHP Alfredo Ruiz. |
| 07/11/21 | St. Louis Cardinals optioned RHP Kodi Whitley to Memphis Redbirds. |
| 07/09/21 | St. Louis Cardinals signed free agent RHP Luis Garcia. |
| 07/09/21 | St. Louis Cardinals optioned RHP Johan Oviedo to Memphis Redbirds. |
| 07/09/21 | St. Louis Cardinals placed RHP Carlos Martinez on the 60-day injured list. Right thumb sprain. |
| 07/08/21 | St. Louis Cardinals optioned RHP Johan Oviedo to Memphis Redbirds. |
| 07/07/21 | St. Louis Cardinals recalled LF Lars Nootbaar from Memphis Redbirds. |
| 07/07/21 | St. Louis Cardinals placed RHP Carlos Martinez on the 10-day injured list. Right thumb sprain. |
| 07/03/21 | St. Louis Cardinals traded 1B John Nogowski to Pittsburgh Pirates. |
| 07/03/21 | St. Louis Cardinals activated RHP Justin Miller. |
| 07/03/21 | St. Louis Cardinals optioned RHP Roel Ramirez to Memphis Redbirds. |
| 07/02/21 | St. Louis Cardinals placed RHP Jack Flaherty on the 60-day injured list. Left oblique. |
| 07/02/21 | St. Louis Cardinals claimed RHP Justin Miller off waivers from Washington Nationals. |
| 07/01/21 | St. Louis Cardinals optioned LF Lars Nootbaar to Memphis Redbirds. |
| 07/01/21 | St. Louis Cardinals activated CF Harrison Bader. |
| 07/01/21 | St. Louis Cardinals signed free agent LHP T.J. McFarland to a minor league contract. |
