Hamels left the ballpark to be with his wife, a former "Survivor" contestant, who went into labor with the couple's first child on Thursday.
Hamels gave up four runs and seven hits in five innings against the Colorado Rockies in Game 2 on Thursday. He left after throwing 82 pitches and rushed out of the dugout when he was pinch-hit for in the fifth inning.
Hamels was notified after he was lifted that his wife went into labor. Manager Charlie Manuel said the distraction possibly affected Hamels' performance.
"It could have bothered him, yes," Manuel said.
Hamels said this week his wife was due "any day."