Do small muscle workouts which will do much more to help stabilize your shoulder than big muscle workouts.
Small Muscle Exercises
1. Lay on side and put arm on top side. Take a small plate (2 or 5 lb weight) and rotate your arm from the elbow to the hand. Move from your stomach all the way up.
2. You can either sit or stand but take small weights in each hand and raise them just above shoulder level in front of you. Don't go to high or you will too much strain on your arm. Also, go at an angle outward and not completely to your front.
3. Same thing but go from your side upward completely at the side and not toward the front.
4. Close grip bench press - this is mainly a chest / tricep exercise but the back of your shoulder will get some benefit as well
5. Reverse butterflys on a weight bench.
Those are a few quick ones and I hope they help. Biggest thing to remember is don't throw the weight but lift the weight. This happens when you have too much weight or get tired. Push yourself but not at the expense of doing it correctly. Also stretch to get range of motion which will be a huge plus as well.
Best of luck on getting healthy and hope you have a successful season.