his recovery for what ever he will have done is not only just about rehab its about a person's individual make. up. Adrien Petersen didnt just heal so well and fast because of his fitness level it has to do with his bodies ability to heal.
Look what happned to Willis McGehee in college. If you havent seen go you tube it. His knee was bent back in the opposite direction.....very severe. yet he came back and has had a good career running the ball. Other players that would have been career ending. A lot depends on the idivduals physiology and make up. They all get the bets docs and care in the NFL