From what I've read, arthritis was his biggest problem, not recovering from the knee surgery. If arthritis is that big a problem at his age, I can't imagine how painful his future is going to be (I've had two kinds of arthritis for 10 years, but I'm twice his age). I don't see him putting himself through the pain. Seems like he's real good with the young players. Perhaps this is a good time for him to look into transitioning to coaching, if he wants to stay in professional baseball.