No future Astros, only former Astros with birthdays today ~
1B Frank Thomas (83)
No, not that Frank Thomas, but this one was good in his own right. Thomas was purchased from the Phillies and played only part of one of his 15 seasons for Houston in 1965, playing in only 23 games before getting shipped out to the Milwaukee Braves. He was a three time All-Star for Pittsburgh in the 1950's and arguably his biggest claim to fame was getting the last put out at the Polo Grounds in September 1957.
PH/UT Jimmy Stewart (73)
No, not that Jimmy Stewart. Stewart was obtained from the Reds as a part of the Joe Morgan - Lee May trade in November of 1971 and played in 129 games for Houston in 1972 and 1973, hitting .207/.273/.262.