[Cloud9Fitness]

Those are great points, especially if you keep your humerus internally rotated which increases the risk of impingement. Also, perhaps I did not state clearly enough that you should rest until pain subsides prior to trying new exercises. However, most individuals I see doing upright rows externally rotate there humerus during the movement. They are also performed in the scapular plane, which moves the greater tubercle of the humerus from the impinging tendons on the acromial. What Eric Cressey does not tell you is what degree of external rotation is needed to avoid impingement. The answer is that impingement can occur at any position of humeral rotation if the scapular upward rotation is insufficient. So it is a case by case situation, and this is why I think it is safe for this case after the pain reduces.

The individual who posted the original complaint had an acute pain on the medial scapula. I always think about impingement, but I am more concerned with teaching correct movement patterns before the impingement occurs. So, building up scapular movement awareness with exercises like PNF raises, pushup pluses, and upright rows (to replace basic shrugs) would be indicated. Of course all of these exercises should be done with a low enough weight that proper upward rotation can be achieved and only if you feel comfortable (pain free) while you are doing them.