The article posted on here from last year in the Journal of Sports Science and Medicine stated that:
"Those pitchers who were found to deviate from these norms (directly towards the plate plus or minus 10 cm) toward open foot position and alignment showed increased kinetics at the shoulder."
"Interestingly, those pitchers who landed in a more 'closed' position (in terms of foot angle, and placement) had no increase in stressful parameters demonstrated"
IMO, pitchers with shoulder problems almost always open early (non-throwing shoulder), consequently releasing early not allowing their arm to get out in front and reach their deceleration phase in a good position. This poor deceleration puts excessive strain on the rear rotator cuff. Chris O would tell you bad timing (forearm vertical) at the start of shoulder rotation also leads to shoulder problems (labrum) but I'm not totally sold on that theory.