No upperbody, just deadlifts/squats/leg workouts

[NJL52]

Don't take training advice from normal people on a forum...
Seek out professional advice from somebody who knows how to train pitchers. Strength/power/size has a very unpredictable effect on pitching performance. If you can't have a trainer on your team, find a way to contact a university coach or somebody who has professional experience.

 

[fortunatesun]

Adding to the last few posts-

Off season is when you want to develop. Once season starts it's just too late. Guys who try this just set themselves back.

Here's a recent article by a strength and conditioning coach who specializes in baseball:

In-Season Training for Baseball

It has some common sense and a sample workout.