Tommy John for starters. Jon Lieber is another (the yankees signed him to a two year deal while recovering if i am not mistaken), Tom Gordon, and Billy Koch just to name a few.
BTW the reason pitcher typically throw harder after TJ operation is because of the workout regime they have to go through while recovering. If your teammate works hard and does what the doctors tell him there is an exceptionally good chance he will be as good or better than he was before.
"I do not think baseball of today is any better than it was 30 years ago... I still think Radbourne is the greatest of the pitchers." John Sullivan 1914-Old athletes never change.