Roger Clemens' left hamstring was sore enough late Saturday night that he was given a cortisone shot after the game, ESPN.com was told by a baseball official who was updated Sunday on Clemens' condition. Because Clemens has responded to these shots in the past, the Astros haven't ruled out the possibility that he can pitch again in this World Series. However, if Clemens can't make his Game 5 start as scheduled Thursday, Astros pitching coach Jim Hickey said it's unlikely the club would opt to bring back Andy Pettitte, Roy Oswalt or Brandon Backe on short rest to make up for Clemens' absence. "It could happen," Hickey said. "But I don't think that's what's going to happen. But things change real quick, especially if you find yourself in a hole. But I just don't think that would happen. It's not very probable right now."