San Francisco Giants pitcher Brian Wilson winds up during his MLB National League baseball game against the St. Louis Cardinals in San Francisco, California, April 8, 2011. REUTERS/Beck Diefenbach (UNITED STATES - Tags: SPORT BASEBALL)
In 2009 Wilson averaged a fastball velocity of 96.47 mph as he cemented himself as one of the elite relief pitchers in baseball with a 2.74 ERA, 2.50 FIP and a 2.36 tRA. In 2010 he took another big step and became arguably the best closer in baseball with a 1.81 ERA, 2.19 FIP and 1.98 tRA while averaging a fastball at 95.84 mph.
This year both his numbers and his fastball seem to have taken a step back. Heading into the All-Star break Wilson has a 3.14 ERA, a 3.24 FIP and a 3.57 tRA. Those are all good numbers but not on the level that we have come to expect from the eccentric closer. On top of everything his fastball has slowed to 94.22 mph this season.
So where did the velocity go?
Here is the chart of every fastball he has thrown since the beginning of 2009:
The orange lines are each fastball while the black line represents the season average. The drop this season is fairly large and quite noticeable.
So what is causing this drop? It doesn't appear that he is sacrificing some mph for control as his walk rate has jumped this seasons to its highest level since his short stint in the majors in 2006.
It is possible that some of it might be arm fatigue after pitching deep into the postseason and notching back to back 70+ inning seasons and always being willing to take the ball with little rest.
The most likely cause however is that he has changed the way that he throws his fastball. In 2009 and 2010 his fastball averaged about 3 and a half inches of tail towards a right handed batter. This season his fastball has averaged 6 and three quarters inches of tail. The answer to the case of the missing velocity is likely that Wilson is giving up some giddy up for more movement.
So far the extra movement hasn't paid off in better numbers but I think that Wilson has earned to have a fairly long leash to try to figure out how to control this new weapon.
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