The 65-year-old Dauer was rushed to a hospital Friday immediately after Houston's parade to celebrate its first World Series title. The emergency surgery was performed at Houston Methodist hospital, where he is now recovering.
Dauer played for the Baltimore Orioles from 1976-1985, winning a World Series with them in 1983. Dauer was hired by the Astros after the 2014 season.
Astros general manager Jeff Luhnow and manager A.J. Hinch say the team is supporting Dauer and his family throughout the recovery.