Stephen Strasburg's rookie season came to end on Aug. 21. Now that he will likely need Tommy John surgery on his right elbow, the 2011 season is in doubt for the 2009 No. 1 overall pick of the Washington Nationals.
Tommy John surgery used to mean the end of a pitcher's career. However, that's no longer the case.
In a sample of notable recent pitchers who underwent Tommy John surgery, I looked at 45 pitchers who pitched at least one season in the majors before the surgery and also pitched at least one season following operation.
I looked at three statistics before and after the surgery, all from Baseball-Reference.com:
• Innings pitched per season (to measure how 'durable' pitchers are after the surgery)
• ERA (the basic rate measure of effectiveness for a pitcher)
• WAR per season (the best way to look at how much total production a pitcher provides)
Per-season statistics were used because players have had the surgery at various points in their careers. The average results for these pitchers (using an unweighted average of ERA so as to not skew those who pitched a lot) are summarized in the table.
Performance Before, After Tommy John Surgery
Sample of 45 Pitchers from Recent Seasons
According to our small sample, a pitcher’s production seemingly declines after Tommy John surgery, but not too much. On average, he pitches about 14 fewer innings per season, sees his ERA increase by about 0.3, and accounts for about a quarter of a win above replacement less per season.
Keep in mind this doesn’t allow for things like age or other factors that could explain the difference, and I don’t know how statistically significant the changes actually are. A better study on the effect of Tommy John surgery on pitcher performance was done by a group of doctors from the Department of Orthopedic Surgery at the University of Pennsylvania that was published in the American Journal of Sports Medicine in April 2007.
These are the major takeaways from the study:
• At the time, about one in nine active MLB pitchers had undergone the procedure.
• Of 68 MLB pitchers who pitched at least one game before undergoing Tommy John surgery (the sample chosen for the study), 56 returned to pitch (82 percent). Those who returned did so at an average of 18.5 months after surgery.
• Those pitchers who returned after surgery had no significant change in ERA or WHIP from before the surgery. Innings pitched per season was not significantly different by the second season after surgery.
• Starters were 2.6 times more likely to require the surgery than relievers. Pitchers with better ERAs and those who spent less time playing in the majors were at increased risk of having the surgery.