Complex sentence: Roscoe Miller (23-13) was the team's first 20-game winner, and his performance contributed to the Tigers third best team ERA (3.30) in the American League.
Split into simpler sentences: Roscoe Miller (23-13) led the team in wins and was the Tigers' first 20-game winner. His performance contributed to a strong pitching staff which had the third lowest ERA (3.30) in the American League.