bodybuildign supplements

I am 6'5" 215 and 18 years old. Im am looking to run a bulk, but would like to put on lean muscle mass beacause i am a baseball player/pitcher. Ive been working out seriously for about 3 years now, and lifting seriosuly for about 1. I eat about 3-4 large meals a day, with 2-3 small snacks...