Pectoral Muscles

How do I increase my Pectoral Muscle size? I suppose this is a non-pitching related question. But… My right pec area is completly normal, but my left has no muscle to it. Its ribby in a way and I would like how to know to build the muscle with dumbbells.

I would caution against excessive chest hypertrophy as a pitcher… that being said…

pushup and weighted pushup variations

flat and incline bench press (careful - use good form)

DB flat and incline bench press and one-arm variations

vary strength (3-5 rep range) and hypertrophy (6-12 rep range) work and make sure to keep your lifting program balanced, at least one pull exercise for every push.