Cubs Roster & Staff
Transactions
| Date | Transaction |
| 05/09/21 | Chicago Cubs sent RHP Shelby Miller on a rehab assignment to Iowa Cubs. |
| 05/07/21 | Chicago Cubs placed CF Ian Happ on the 10-day injured list. Left rib contusion. |
| 05/07/21 | Chicago Cubs designated LHP Kyle Ryan for assignment. |
| 05/07/21 | Chicago Cubs recalled RHP Jason Adam from Iowa Cubs. |
| 05/07/21 | Chicago Cubs selected the contract of LF Nick Martini from Iowa Cubs. |
| 05/05/21 | Chicago Cubs optioned RHP Kohl Stewart to Iowa Cubs. |
| 05/05/21 | Chicago Cubs optioned RHP Tyson Miller to Iowa Cubs. |
| 05/05/21 | Chicago Cubs placed C Austin Romine on the 60-day injured list. |
| 05/04/21 | Chicago Cubs selected the contract of 2B Ildemaro Vargas from Iowa Cubs. |
| 05/04/21 | Chicago Cubs recalled RHP Kohl Stewart from Iowa Cubs. |
| 05/04/21 | Chicago Cubs signed free agent LHP Alex Katz to a minor league contract. |
| 05/04/21 | Chicago Cubs recalled RHP Keegan Thompson from Cubs Alternate Training Site. |
| 05/04/21 | Chicago Cubs placed RHP Jake Arrieta on the 10-day injured list. Right thumb abrasion. |
| 05/04/21 | Chicago Cubs signed free agent RHP Austin Krzeminski to a minor league contract. |
| 05/03/21 | Chicago Cubs recalled LHP Kyle Ryan from Iowa Cubs. |
| 05/03/21 | Chicago Cubs activated CF Joc Pederson from the 10-day injured list. |
| 05/03/21 | Chicago Cubs placed RHP Dan Winkler on the 10-day injured list. Right triceps tendinitis. |
| 05/03/21 | Chicago Cubs optioned RHP Keegan Thompson to Cubs Alternate Training Site. |
| 05/03/21 | Chicago Cubs placed SS Nico Hoerner on the 10-day injured list. Left forearm strain. |
| 05/03/21 | Chicago Cubs signed free agent LHP Ryan Kellogg to a minor league contract. |
| 05/01/21 | Chicago Cubs optioned LHP Kyle Ryan to Iowa Cubs. |
| 05/01/21 | Chicago Cubs recalled RHP Keegan Thompson from Iowa Cubs. |
