Cardinals Roster & Staff
Transactions
| Date | Transaction |
| 06/29/21 | St. Louis Cardinals sent CF Harrison Bader on a rehab assignment to Memphis Redbirds. |
| 06/28/21 | St. Louis Cardinals selected the contract of RHP Roel Ramirez from Memphis Redbirds. |
| 06/28/21 | St. Louis Cardinals optioned RHP Seth Elledge to Memphis Redbirds. |
| 06/28/21 | St. Louis Cardinals selected the contract of LHP Brandon Waddell from Memphis Redbirds. |
| 06/28/21 | St. Louis Cardinals optioned RHP Jake Woodford to Memphis Redbirds. |
| 06/28/21 | St. Louis Cardinals designated 1B John Nogowski for assignment. |
| 06/26/21 | St. Louis Cardinals sent RHP Kodi Whitley on a rehab assignment to Springfield Cardinals. |
| 06/25/21 | St. Louis Cardinals sent CF Harrison Bader on a rehab assignment to Palm Beach Cardinals. |
| 06/24/21 | Colorado Rockies claimed LHP Bernardo Flores Jr. off waivers from St. Louis Cardinals. |
| 06/23/21 | St. Louis Cardinals recalled RHP Seth Elledge from Memphis Redbirds. |
| 06/23/21 | St. Louis Cardinals placed RHP Daniel Ponce de Leon on the 10-day injured list. Right shoulder discomfort. |
| 06/22/21 | St. Louis Cardinals selected the contract of LF Lars Nootbaar from Memphis Redbirds. |
| 06/22/21 | St. Louis Cardinals optioned CF Lane Thomas to Memphis Redbirds. |
| 06/22/21 | St. Louis Cardinals designated LHP Bernardo Flores Jr. for assignment. |
| 06/18/21 | St. Louis Cardinals optioned RF Justin Williams to Memphis Redbirds. |
| 06/17/21 | St. Louis Cardinals placed 2B Max Moroff on the 60-day injured list. Left shoulder subluxation. |
| 06/17/21 | St. Louis Cardinals signed free agent LHP Wade LeBlanc. |
| 06/17/21 | St. Louis Cardinals optioned RHP Seth Elledge to Memphis Redbirds. |
| 06/15/21 | St. Louis Cardinals activated LHP Kwang Hyun Kim from the 10-day injured list. |
| 06/15/21 | St. Louis Cardinals optioned RHP Angel Rondon to Memphis Redbirds. |
| 06/15/21 | St. Louis Cardinals signed free agent LHP Sean Kealey to a minor league contract. |
| 06/14/21 | St. Louis Cardinals signed free agent RHP Brandon Dickson to a minor league contract. |
| 06/14/21 | St. Louis Cardinals signed free agent RHP Paul Schwendel to a minor league contract. |
| 06/12/21 | St. Louis Cardinals signed free agent RHP Juan Severino to a minor league contract. |
| 06/12/21 | St. Louis Cardinals signed free agent LHP Kevin McGovern to a minor league contract. |
| 06/12/21 | St. Louis Cardinals signed free agent C Carlos Linarez to a minor league contract. |
| 06/12/21 | St. Louis Cardinals signed free agent LHP Kevin Marnon to a minor league contract. |
| 06/12/21 | St. Louis Cardinals signed free agent RHP Ronny Oliver to a minor league contract. |
| 06/12/21 | St. Louis Cardinals signed free agent RHP Cory Thompson to a minor league contract. |
| 06/11/21 | St. Louis Cardinals activated SS Paul DeJong. |
| 06/11/21 | St. Louis Cardinals sent RF Justin Williams on a rehab assignment to Memphis Redbirds. |
| 06/10/21 | St. Louis Cardinals optioned LHP Brandon Waddell to Memphis Redbirds. |
| 06/10/21 | St. Louis Cardinals optioned 1B John Nogowski to Memphis Redbirds. |
| 06/06/21 | St. Louis Cardinals sent LHP Tyler Webb outright to Memphis Redbirds. |
| 06/06/21 | St. Louis Cardinals claimed LHP Brandon Waddell off waivers from Baltimore Orioles. |
| 06/05/21 | St. Louis Cardinals sent SS Paul DeJong on a rehab assignment to Memphis Redbirds. |
| 06/05/21 | St. Louis Cardinals placed RF Justin Williams on the 10-day injured list. Neck stiffness. |
| 06/05/21 | St. Louis Cardinals recalled RHP Angel Rondon from Memphis Redbirds. |
| 06/05/21 | St. Louis Cardinals placed LHP Kwang Hyun Kim on the 10-day injured list. Right lower back stiffness. |
| 06/05/21 | St. Louis Cardinals recalled 1B John Nogowski from Memphis Redbirds. |
| 06/03/21 | St. Louis Cardinals activated LHP Andrew Miller. |
| 06/03/21 | St. Louis Cardinals designated LHP Tyler Webb for assignment. |
| 06/01/21 | St. Louis Cardinals placed RHP Jack Flaherty on the 10-day injured list. Left oblique. |
| 06/01/21 | St. Louis Cardinals recalled RHP Johan Oviedo from Memphis Redbirds. |