While examining a 17-year-old pitcher for a knee injury last year in Nashville, Dr. Damon H. Petty was asked a chilling question by the teenager and his father: If reconstructive elbow surgery were performed on his healthy throwing arm, might he gain some speed on his fastball?
Dr. Petty said he dissuaded them, explaining that was a myth, a “dangerous notion to entertain,” and that ligament reconstruction on a healthy arm would not improve his pitching “one iota.”
The procedure is commonly known as Tommy John surgery, named after the former major league pitcher on whom it was first performed in 1974. The surgery has become so reliable, with a success rate of 80 to 85 percent, that it has prolonged the careers of hundreds of major leaguers. About one in seven pitchers in the major leagues this season has had the surgery.|NY Times|
No evidence of any kind is given for the claim that the performance enhancing reputation of Tommy John Surgery is a mere myth. Maybe it is, but there sure are a lot of anecdotal reports of major league pitchers who throw harder after the surgery than before.
Leaving that aside, do you think we can assume that if one in seven major league pitchers have had the surgery, it wasn't medically necessary in all cases? And that when the surgery wasn't medically necessary, it was sought because it was thought (perhaps wrongly) to increase velocity?