Complex sentence: In 1920, Palace became founder members of the Third Division and Bateman made the transition to professional football becoming a regular in the side that won the inaugural Third Division title in 1920--21, making 32 appearances but without scoring.
Split into simpler sentences: In 1920, Palace became founder members of the Third Division and Bateman made the transition to professional football. He became a regular in the side that won the inaugural Third Division title in 1920--21, making 32 appearances but without scoring.