He said the hamstring felt about the same on Saturday as it did on Friday. He tweaked it while trying to field a ground ball in the second inning and left the game after 1 2/3 innings.
"We'll figure it out today," Gonzalez said. "Yesterday was really bad."
Astros interim manager Tony DeFrancesco is preparing for the possibility that Gonzalez won't be ready to pitch on Friday in Milwaukee, when he would be scheduled to come up in the rotation.
"He's a little bit sore, which we expected," DeFrancesco said. "We'll see how it responds. Nobody really knows how bad it was. He just couldn't drive off his back side yesterday."
Fernando Rodriguez, who tossed 3 1/3 scoreless innings in relief of Gonzalez, could be a candidate for a spot start. With 10 relievers in the bullpen, the Astros also might be able to piece together a game.