Exactly, two different things. Which makes your assertion that his back is healthy enough to play NFL football, based on his ability to golf, is flat out wrong. Because they are two completely different things.
The risk of injury while playing golf can be minimized because you are swinging the club in a controlled environment and you can use proper form when swinging, to minimize the risk of injury.
There is no proper form for being leveled by a 300 pound man, while simultaneously trying to throw a football.