| | | Wednesday, August 6th, 1980 | | Placed LF Greg Turner on the 15-day disabled list. |
| Tuesday, July 22nd, 1980 | | Activated SP Louis Hanson from the disabled list. |
| Saturday, July 19th, 1980 | | Placed SP Mike Moore on the 15-day disabled list. |
| Sunday, June 15th, 1980 | | Received SP Brock Alston from Double A Beeville. | | Released MR Brock Alston. | | Drafted MR Rob Dotson in the 1980 first-year player draft (Round 6, Pick 11, 115th overall pick). | | Drafted 2B Lee Hayes in the 1980 first-year player draft (Round 7, Pick 11, 136th overall pick). | | Drafted MR Domingo Martínez in the 1980 first-year player draft (Round 8, Pick 11, 156th overall pick). | | Drafted LF Pedro Limón in the 1980 first-year player draft (Round 9, Pick 11, 176th overall pick). | | Drafted MR Paul Brown in the 1980 first-year player draft (Round 10, Pick 11, 196th overall pick). |
| Tuesday, May 27th, 1980 | | Activated CL Tim Smith from the disabled list. |
| Wednesday, May 14th, 1980 | | Placed SP Carlin Chambers on the 15-day disabled list. | | Placed MR Raúl Lucero on the 15-day disabled list. |
| Sunday, May 11th, 1980 | | Placed CL Tim Smith on the 15-day disabled list. |
| Saturday, May 10th, 1980 | | Placed SP Louis Hanson on the 15-day disabled list. |
| Monday, April 21st, 1980 | | Placed CF António Moore on the 15-day disabled list. |
| Sunday, April 20th, 1980 | | Placed SS Jim Ford on the 15-day disabled list. |
| Thursday, September 27th, 1979 | | Activated SP Carlin Chambers from the disabled list. |
| Friday, August 31st, 1979 | | Signed hitting coach Myron Ashley. |
| Thursday, August 23rd, 1979 | | Hitting Coach Tim James leaves the team, his contract was not renewed. | | Released MR Keith Washington. |
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