Third baseman Jimmy Paredes was among Houston's six roster cuts on Friday.
The 23-year-old Paredes hit .286 in 46 games with the Astros last season. He came into camp with a chance to be the starting third baseman on opening day. He hit .190 in 10 exhibition games.
He was optioned to Triple-A Oklahoma City along with outfielder Fernando Martinez and pitcher Aneury Rodriguez.
Pitchers Xavier Cedeno and Jose Valdez and outfielder Brad Snyder were reassigned to the minor league camp. That leaves 41 players in camp for the Astros, who lost a franchise-worst 106 games in 2011.