Cubs Roster & Staff
Transactions
| Date | Transaction |
| 06/30/21 | Chicago Cubs placed C Jose Lobaton on the 60-day injured list. Left shoulder sprain. |
| 06/30/21 | Chicago Cubs signed free agent RHP Adam Heidenfelder to a minor league contract. |
| 06/30/21 | Chicago Cubs selected the contract of C Taylor Gushue from Iowa Cubs. |
| 06/29/21 | Chicago Cubs recalled RHP Tommy Nance from Iowa Cubs. |
| 06/29/21 | Chicago Cubs selected the contract of LHP Adam Morgan from Iowa Cubs. |
| 06/29/21 | Chicago Cubs placed RHP Ryan Tepera on the 10-day injured list. Left calf strain. |
| 06/29/21 | Chicago Cubs optioned RHP Trevor Megill to Iowa Cubs. |
| 06/29/21 | Chicago Cubs placed 3B Matt Duffy on the 60-day injured list. Low back strain. |
| 06/28/21 | Chicago Cubs recalled RHP Trevor Megill from Iowa Cubs. |
| 06/28/21 | Chicago Cubs optioned RHP Tommy Nance to Iowa Cubs. |
| 06/27/21 | Chicago Cubs sent RHP Trevor Williams on a rehab assignment to Iowa Cubs. |
| 06/27/21 | Chicago Cubs signed free agent LHP Dalton Stambaugh to a minor league contract. |
| 06/27/21 | Chicago Cubs sent 2B Nico Hoerner on a rehab assignment to Iowa Cubs. |
| 06/27/21 | Chicago Cubs sent LHP Justin Steele on a rehab assignment to Iowa Cubs. |
| 06/26/21 | Chicago Cubs sent RHP Dillon Maples on a rehab assignment to Iowa Cubs. |
| 06/25/21 | Chicago Cubs signed free agent SS Geuri Lubo to a minor league contract. |
| 06/22/21 | New York Mets claimed RHP Robert Stock off waivers from Chicago Cubs. |
| 06/22/21 | Chicago Cubs signed free agent 1B Matt Warkentin to a minor league contract. |
| 06/21/21 | Chicago Cubs optioned LHP Kyle Ryan to Iowa Cubs. |
| 06/21/21 | Chicago Cubs activated RHP Adbert Alzolay from the 10-day injured list. |
| 06/20/21 | Chicago Cubs designated RHP Robert Stock for assignment. |
| 06/20/21 | Chicago Cubs recalled LHP Kyle Ryan from Iowa Cubs. |
| 06/20/21 | Chicago Cubs optioned RHP Cory Abbott to Iowa Cubs. |
| 06/19/21 | Chicago Cubs selected the contract of SS Edwin Figuera from York Revolution. |
| 06/18/21 | Chicago Cubs signed free agent C Harrison Wenson to a minor league contract. |
| 06/17/21 | Chicago Cubs recalled LHP Brad Wieck from Iowa Cubs. |
| 06/17/21 | Chicago Cubs optioned RHP Robert Stock to Iowa Cubs. |
| 06/16/21 | Chicago Cubs selected the contract of RHP Robert Stock from Iowa Cubs. |
| 06/16/21 | Chicago Cubs optioned RHP Trevor Megill to Iowa Cubs. |
| 06/16/21 | Chicago Cubs placed RHP Dillon Maples on the 10-day injured list. Right triceps strain. |
| 06/16/21 | Chicago Cubs recalled RHP Cory Abbott from Iowa Cubs. |
| 06/16/21 | Chicago Cubs selected the contract of RHP Mike Hauschild from Lexington Legends. |
| 06/16/21 | Chicago Cubs placed C P.J. Higgins on the 60-day injured list. Right forearm strain. |
| 06/14/21 | Chicago Cubs signed free agent C Tim Susnara to a minor league contract. |
| 06/13/21 | Chicago Cubs sent RHP Dakota Chalmers outright to Tennessee Smokies. |
| 06/13/21 | Chicago Cubs signed free agent RHP Jose Almonte to a minor league contract. |
| 06/12/21 | Chicago Cubs recalled RHP Trevor Megill from Iowa Cubs. |
| 06/12/21 | Chicago Cubs optioned RHP Kohl Stewart to Iowa Cubs. |
| 06/11/21 | Chicago Cubs designated RHP Dakota Chalmers for assignment. |
| 06/11/21 | Chicago Cubs selected the contract of C Jose Lobaton from Iowa Cubs. |
| 06/11/21 | Chicago Cubs placed C P.J. Higgins on the 10-day injured list. Right forearm strain. |
| 06/08/21 | Chicago Cubs placed RHP Adbert Alzolay on the 10-day injured list. Right middle finger blister. |
| 06/08/21 | Chicago Cubs recalled RHP Kohl Stewart from Iowa Cubs. |
| 06/08/21 | Chicago Cubs optioned RHP Cory Abbott to Iowa Cubs. |
| 06/08/21 | Chicago Cubs activated RHP Alec Mills. |
| 06/07/21 | Chicago Cubs signed free agent 2B Carlos Sepulveda to a minor league contract. |
| 06/07/21 | Chicago Cubs sent LF Nick Martini outright to Iowa Cubs. |
| 06/07/21 | Chicago Cubs optioned RHP Kohl Stewart to Iowa Cubs. |
| 06/07/21 | Chicago Cubs activated CF Jake Marisnick. |
| 06/05/21 | Chicago Cubs activated RF Jason Heyward. |
| 06/05/21 | Chicago Cubs optioned LHP Brad Wieck to Iowa Cubs. |
| 06/05/21 | Chicago Cubs recalled RHP Cory Abbott from Iowa Cubs. |
| 06/05/21 | Chicago Cubs claimed RHP Dakota Chalmers off waivers from Minnesota Twins. |
| 06/05/21 | Chicago Cubs designated LF Nick Martini for assignment. |
| 06/05/21 | Chicago Cubs optioned RHP Dakota Chalmers to Tennessee Smokies. |
| 06/04/21 | Texas Rangers claimed RHP Tyson Miller off waivers from Chicago Cubs. |
| 06/02/21 | Chicago Cubs sent CF Jake Marisnick on a rehab assignment to Iowa Cubs. |
| 06/02/21 | Chicago Cubs sent RF Jason Heyward on a rehab assignment to Iowa Cubs. |
| 06/02/21 | Chicago Cubs activated RHP Trevor Megill. |
| 06/02/21 | Chicago Cubs optioned RHP Trevor Megill to Iowa Cubs. |