Complex sentence: As the name suggests, the pitching coach is generally a former pitcher except in the case of Dave Duncan, the current pitching coach of the St. Louis Cardinals who was never a pitcher during his playing career as he instead was a catcher.
Split into simpler sentences: As the name suggests, the pitching coach is generally a former pitcher. One exception is Dave Duncan, the current pitching coach of the St. Louis Cardinals who was never a pitcher during his playing career as he instead was a catcher.