Update on where we are at:
My son Nick had a lesion that was 6 mm x 7mm centrally located with a loose body. Arthroscopic surgery at the University of Wisconsin to remove the loose fragment, debridement, and microfracture on 8/31. He was in a sling until 9/9 and then began physical therapy with about 6 weeks of range of motion and 6 weeks of strengthening therapy. To keep him sane we continued to have him take infield ground balls a month after surgery which kept him optimistic about rehab and helped his range of motion.
He was cleared to take batting practice and begin rehab throwing on 12/1 which is where we are at now. Throwing rehab program is a gradual build up over 4-6 weeks from 30 feet to 120 feet and then on to UW Sports Medicine's throwing program sometime in January. He throws and hits with no pain, full range of motion, and all looks good so far.