Yes, but who is saying he hasn't been able to regenerate his nerves? His surgeoon says he can play.Did his doctors mention he will not have nerve regeneration? Did they mention anything at all about his arm strngth and accuracy? Where is all the worry about nerve regeneration coming from? If his doctor cleared him medically, that means he's capable of playing. Would his doctors clear him if they didn't think he was going to have good results? Clearly they would have told him there are reservations if they felt that way. Unless what Payton is telling people is not exactly what his doctors told him. But i doubt that.
Based on what do you have this "likely scenario"? Are you a specialist is this field? As far as I know, the specialists cleared him to resume playing. Based on that I expect him to play and play at a high level.