Complex sentence: However, his most memorable start of the season was his final, in which he pitched fifteen innings of shutout ball against the Philadelphia Phillies in a game that was eventually declared a 0-0 tie after eighteen innings.
Split into simpler sentences: However, his most memorable start of the season was his final, in which he pitched fifteen innings of shutout ball against the Philadelphia Phillies. The game was declared a 0-0 tie after eighteen innings.