Grossman, who hurt the oblique taking a swing in a game, was not sure how soon he would be ready to take batting practice.
"It just depends on how I feel," Grossman said. "It's just frustrating, sitting and not being able to do anything to help the team."
Grossman, a switch hitter, is batting .268 in 63 games this season with four homers and 21 RBIs.
The Astros have played lately with Trevor Crowe in left, Brandon Barnes in center and L.J. Hoes in right most games.
Crowe did not start Tuesday night's game because manager Bo Porter wanted to give him a day's rest. Marc Krauss replaced Crowe in left field and Jimmy Paredes, who was called up Sept. 8, started in right.
Gene Duffey is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.