Astros Roster & Staff
Transactions
| Date | Transaction |
| 09/30/21 | Houston Astros sent RHP Zack Greinke on a rehab assignment to Sugar Land Skeeters. |
| 09/30/21 | Houston Astros activated RHP Kendall Graveman from the paternity list. |
| 09/30/21 | Houston Astros optioned RHP Peter Solomon to Sugar Land Skeeters. |
| 09/29/21 | Houston Astros optioned RHP Josh James to Sugar Land Skeeters. |
| 09/29/21 | Houston Astros activated LF Michael Brantley from the 10-day injured list. |
| 09/28/21 | Houston Astros placed RHP Kendall Graveman on the paternity list. |
| 09/28/21 | Houston Astros signed free agent RHP Alain Pena to a minor league contract. |
| 09/28/21 | Houston Astros recalled RHP Josh James from Sugar Land Skeeters. |
| 09/26/21 | Houston Astros optioned RHP Seth Martinez to Sugar Land Skeeters. |
| 09/26/21 | Houston Astros activated RHP Jake Odorizzi from the 10-day injured list. |
| 09/24/21 | Houston Astros signed free agent C Daniel Castro to a minor league contract. |
| 09/24/21 | Houston Astros recalled RHP Peter Solomon from Sugar Land Skeeters. |
| 09/24/21 | Houston Astros placed RHP Zack Greinke on the 10-day injured list. Neck soreness. |
| 09/23/21 | Houston Astros sent RHP Pedro Baez on a rehab assignment to Sugar Land Skeeters. |
| 09/23/21 | Houston Astros activated RHP Ryne Stanek from the paternity list. |
| 09/23/21 | Houston Astros sent RHP Tyler Ivey on a rehab assignment to Sugar Land Skeeters. |
| 09/23/21 | Houston Astros optioned RHP Josh James to Sugar Land Skeeters. |
| 09/20/21 | Houston Astros recalled RHP Brandon Bielak from Sugar Land Skeeters. |
| 09/20/21 | Houston Astros placed RHP Ryne Stanek on the paternity list. |
| 09/20/21 | Houston Astros selected the contract of RHP Seth Martinez from Sugar Land Skeeters. |
| 09/20/21 | Houston Astros placed SS Freudis Nova on the 60-day injured list. Left knee ACL tear. |
| 09/20/21 | Houston Astros optioned RHP Peter Solomon to Sugar Land Skeeters. |
| 09/18/21 | Houston Astros recalled RHP Peter Solomon from Sugar Land Skeeters. |
| 09/18/21 | Houston Astros optioned RHP Brandon Bielak to Sugar Land Skeeters. |
| 09/17/21 | Houston Astros optioned C Garrett Stubbs to Sugar Land Skeeters. |
| 09/17/21 | Houston Astros activated C Jason Castro. |
| 09/17/21 | Houston Astros sent 2B Robel Garcia outright to Sugar Land Skeeters. |
| 09/17/21 | Houston Astros sent RHP Tyler Ivey on a rehab assignment to FCL Astros. |
| 09/16/21 | Houston Astros signed free agent RHP Hector Cuevas to a minor league contract. |
| 09/16/21 | Houston Astros signed free agent RHP Normar Torres to a minor league contract. |
| 09/15/21 | Houston Astros optioned 1B Taylor Jones to Sugar Land Skeeters. |
| 09/15/21 | Houston Astros placed RHP Rafael Montero on the 60-day injured list. Right shoulder discomfort. |
| 09/15/21 | Houston Astros designated 2B Robel Garcia for assignment. |
| 09/15/21 | Houston Astros optioned RHP Andre Scrubb to Sugar Land Skeeters. |
| 09/15/21 | Houston Astros sent C Jason Castro on a rehab assignment to Corpus Christi Hooks. |
| 09/15/21 | Houston Astros placed LF Michael Brantley on the 10-day injured list. Right knee soreness. |
| 09/15/21 | Houston Astros recalled RHP Josh James from Sugar Land Skeeters. |
| 09/14/21 | Houston Astros placed RHP Jake Odorizzi on the 10-day injured list. Right foot soreness. |
| 09/14/21 | Houston Astros activated RHP Zack Greinke from the 10-day injured list. |
| 09/13/21 | Houston Astros sent 1B Taylor Jones on a rehab assignment to Sugar Land Skeeters. |
| 09/13/21 | Houston Astros sent 2B Jacob Wilson outright to Sugar Land Skeeters. |
| 09/13/21 | Houston Astros sent C Jason Castro on a rehab assignment to Sugar Land Skeeters. |
| 09/10/21 | Houston Astros signed free agent LHP Yanquiel Sanchez to a minor league contract. |
| 09/05/21 | Houston Astros optioned RHP Josh James to Sugar Land Skeeters. |
| 09/05/21 | Houston Astros selected the contract of SS Marwin Gonzalez from Sugar Land Skeeters. |
| 09/03/21 | Houston Astros selected the contract of CF Jose Siri, and from Sugar Land Skeeters. |
| 09/03/21 | Houston Astros sent RHP Andre Scrubb on a rehab assignment to Sugar Land Skeeters. |
| 09/03/21 | Houston Astros optioned RHP Enoli Paredes to Sugar Land Skeeters. |
| 09/03/21 | Houston Astros activated RF Chas McCormick. |
| 09/03/21 | Houston Astros optioned 2B Robel Garcia to Sugar Land Skeeters. |
| 09/01/21 | Houston Astros recalled RHP Enoli Paredes from Sugar Land Skeeters. |
| 09/01/21 | Houston Astros activated RHP José Urquidy from the 10-day injured list. |