I'm amazed a surgery could heal it quicker and potentially within three weeks.
Clear the crud out of the way is the best way to describe it or "out with the old and in with the new".
Not sure if he has had past shoulder injuries but it is hard to imagine he hasn't had at least minor ones over time. Spurs build up, fraying happens to the tissue without being torn and clearing that stuff up does wonders. I was in pain and had more then one dr send me off to physical therapy and the result was nil. A friend sent me to his orthopedic surgeon who is also the surgeon for the Mariners and he said PT was pointless and that the shoulder couldn't heal from past injuries because of those issues.
Like i said earlier two weeks after surgery i was swinging a golf club and hadn't done that pain free for a couple of years.
On the flip side of that i had a surgery several years ago on my shoulder (rotator) that hobbled me for months on end but what they did wrong with that was not repairing the minor issues such as the fraying and the spurs in the AC joint.