My Son Was Pitching And After His Upper Arm And

My son was pitching and after his upper arm and shoulder were very painful. He could not raise his arm from his side easily and he had numbness in his arm and hand. The ER doctor felt it too be a very strained upper bicep. He has been icing and taking ibuprofen. It has been about 10 days and he is feeling much better. He has lightly started throwing and has been fine. Today he finally got into the physical therapist and she is concerned that he tore his labrum. He is going to be scheduled for an MRI in next couple of days. The X-ray was fine. Could it be a torn labrum?