Houston relief pitcher Doug Brocail left Sunday's game against Atlanta after apparently injuring his left leg on a play at first base in the eighth inning.
First baseman Lance Berkman made a diving stop on Kelly Johnson's grounder, and Brocail covered the bag.
Brocail's left leg seemed to buckle as he caught Berkman's throw and touched first base.
Brocail fell over first base and remained on the ground for about a minute before being helped to his feet. Unable to walk off the field, he was driven off on a cart.
There was no immediate report on his injury.
The 41-year-old reliever came off the disabled list on April 26. He had been out since April 13 with a strained right rotator cuff.