Also there may come a time where he just doesn't feel like doing it any more, even if he still can. These guys with long careers often seem to just tire of it after a while. There's nothing he hasn't accomplished. WS title, perfect game, no hitter. He's made a boatload of money. One off season he may just say "that's enough" and retire and focus on volunteer work and stuff. He seems like that kind of guy.