Doing nothing can be/likely is a sign that he doesn't have the confidence to use his injured shoulder, his fitness isn't there yet, or any number of things.
If you want to describe how he's wrestling as regression, fine by me, though the description doesn't matter much.
He's not performing like the top recruit he was. Whether that's physical, mental, a combination or he's somehow lost his ability to wrestle, the question he and PSU have to answer is whether they can change the direction this thing is going.
Because I don't think it's likely he forgot how to wrestle, I'm still leaning toward the recovery from the injury, both physically and mentally, is why he looks like he does. It's not a simple thing for everyone to overcome when you suddenly can't perform the way you've always been able to.