Baseball pitchers can avoid significant shoulder and elbow injuries however they need two things, a strong posterior rotator cuff, internal mobility and pronation of the forearm through release point. If any pitcher can get these three things right, you will eliminate shoulder issues.
 
The posterior cuff is the back side of the shoulder. You can see from the photo, there is less muscle mass on the back side (Posterior) of the shoulder compared to the front side of the shoulder (Anterior side).
Throwing athletes easily strengthen the front side of their shoulders by doing day to day activities however the posterior side gets far less usage. Also, just by practicing your sport. You gain strength in the front part of your shoulder. Many athletes neglect the posterior side of the rotator cuff in their workouts which lead to instability in the shoulder and lead to muscle atrophy (shrinkage) and ultimately injury.
Common injuries by having a weak posterior shoulder/rotator cuff and instability are impingement, labrum tears, rotator cuff tears and ucl injuries. In my next article I will be talking about exercise that prevent these types of injuries in overhead throwing athletes especially baseball pitchers. Till next time.