Hello Cory Kent,
You will want to make sure the shoulders are strong and balanced. Work with a personal trainer or athletic trainer to find any imbalance.
Do exercises for the core and rotator cuff, don’t overdo throwing and try rear throwing moves to offset the front throwing.
Do not overdo training on one thing; work the entire body. Remember to stretch, eat well and allow enough rest.
Natalie aka NAPS 2 B Fit.
Pitching isn’t so much about the shoulder as it is about the hips and thoracic spine. Being able to go through extension and a huge amount of rotation in the thoracic will help to load the shoulder for throwing the ball. This means training the core in a different way than sit-ups. You want to try and create an elastic recoiling through the front core, meaning to stretch the core in a way that represents throwing, and use that ‘stretch’ as a slingshot (similar to releasing a rubber band) to throw the ball effectively. Standing with rotation exercises would be a good idea here.
For the lower body, getting a lot of rotation through the hips would be important. Rotational lunges both away from standing leg and crossing standing leg are needed for throwing. Then progressing these movements to single leg balance will help with the deceleration of the throw (where the pitcher tends to hurt the shoulder).
I think an important concept for pitchers, aside from various exercise strategies, is to limit the number of pitches thrown as much as possible. It is important to work with the players coaches as well. Even in the pros pitchers are throwing way too many pitches still. Managers have a conflict rationally when a pitcher is doing well, to pull them from a game. And even in the case of a pitcher not doing well, managers and pitchers alike are reluctant to pull a pitcher from a game or accept being pulled. The ego thing is dangerous. Pitchers want to pitch. But the repetitious nature of pitching is the base cause of pitching injuries. Youth baseball is all over this now.