Roger Clemens was once again the Rocket, but left after five innings with a groin injury.
The Chicago Cubs rallied with four runs in the eighth for a 4-2 victory Tuesday night.
"It's more than a mild strain, but I know my body and I didn't tear it," Clemens said. "I'm OK. It's iced down and numb and we'll start treating it tomorrow."
Clemens Leaves Game With Strained Groin