He returned after the injury, but was limping and was replaced by Dan Orlovsky to start the third quarter.
He said he hurt his foot when it caught the rubber on the sideline as he ran out of bounds.
"I just felt a little something in my ankle and it kind of progressively got a little sore," Schaub said. "I was able to stay in there and just came in at the half and figured it was best to just get some treatment on it and proceed that way."
Schaub was 10 of 14 for 108 yards with one interception. He said he expects to play Friday.
Copyright 2009 by The Associated Press