The NFL, if it truly cared about player safety, should allow the Dolphins to pay Tua an injury settlement and have it not count against their salary cap. Everybody is happy and no one is punished.
This presumes facts that are unknown. Does Tua want to walk away? Are the Dolphins resisting letting him walk away based on salary cap concerns?
The elephant in the room here is what to do when the player doesn’t want to stop. At present, the process is that whether the player can continue to play is a medical question - and it’s based on the player’s current symptoms and response in the evaluation. After all symptoms cease, the question of long-term health is for the player. Neither the NFL nor the neurologists take that decision away from the player - it’s his life and his livelihood.
Many think there should be more strict rules about forcing retirement after repeated concussion incidents. Forcing someone away from the sport for their long-term health when they are otherwise not experiencing any symptoms or manifestations - especially if they don’t want to retire - is a very challenging question.
I think Tua’s contract guaranteed money still applies in the event of an injury retirement. He’s made $73M and I think he would be owed additional amounts even if he retired due to injury. I don’t think the Dolphins have leverage to prevent him from doing that. But I don’t think he wants that - perhaps that will change after this one.