Complex sentence: Later in 1926, he went on to be one of the first players signed up by the promoter Charles C. Pyle to play in his professional tennis league; after a split with Pyle, he joined Vincent Richards in forming an association of professional tennis players.
Split into simpler sentences: Later in 1926, he went on to be one of the first players signed up by the promoter Charles C. Pyle to play in his professional tennis league. After a split with Pyle, he joined Richards in forming an association of professional tennis players.