I think Buff and the NHLPA are going to argue negligence on the side of the team doctors at least it seems like that. But I think they are waiting to see if he actually does recover as that may have even further implications against our team doctors misdiagnosing an injury that may have led to the end of his career. At least that's what I'm getting out of it.
Whether they argue that or not I don't see his recovery affecting the arb process one way or another. This is not like a civil lawsuit over responsibility for an injury. In that case the settlement depends on the degree of loss. In hockey, injuries are part of the business. If injured and unable to play, players still get full pay - until their contracts expire. Players don't get to sue their teams or the league after they retire because they have trouble climbing stairs on their banged up knees.
In this case, if it is accepted as a hockey injury (which I expect it will be) then Buff is entitled to full pay till the end of next season. The team and league appear to be arguing that there was no hockey injury. It was all signed off at the end of last season. If they win then Buff is not entitled to be paid.
Assuming it is accepted as a hockey injury Buff did not follow procedure in dealing with it. He did not report to the team. At that point the arbitrator has to decide what to do about it. What consequences are there for Buff's failure to report? If the suspension is upheld, how does Buff go about getting reinstated?
Buff's side, the NHLPA will argue that Buff was not satisfied with the treatment he got and that he was entitled to get treated elsewhere. The league will agree to that but argue that he should have reported first and kept the team involved in the treatment even though it was not the team medical staff treating him.
Both sides have legitimate points. Buff and the Jets would possibly have been able to come to a settlement but the league and the NHLPA both want to win a point, setting some kind of precedent.
I don't see anywhere in there that his recovery to playing level, or lack of it has any effect on the decision. The arbitrator will determine how Buff gets the suspension lifted. The effective date of lifting the suspension puts him back on the payroll, whether he can play at that time or not.