The Astros are promoting top prospect Jonathan Singleton to Triple-A Oklahoma City. He might have started the season there if he didn't have to miss the first 50 games of the season for a positive marijuana test. Singleton has batted .271/.397/.627 with five homers and 13 RBI over 17 games between Low- and Double-A since returning from his suspension. The 21-year-old could possibly push for a call-up later this season.