Offseason
- October 26, 1979: Keith Drumright was sent by the Astros to the Kansas City Royals to complete an earlier deal (the Astros sent a player to be named later to the Royals for George Throop) made on April 27, 1979.
- November 19, 1979: Nolan Ryan was signed as a free agent by the Astros.
- January 31, 1980: Joe Morgan was signed as a free agent by the Astros.
- February 21, 1980: Frank Riccelli was released by the Astros.
Read more about this topic: 1980 Houston Astros Season