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Wainwright’s increasingly effective curve

By Ian Walton

Following Adam Wainwright’s strong seven-inning, two-run outing Saturday that was unfortunately spoiled by a lack of run support and a shaky bullpen, I decided to delve a little deeper into what has made the 28-year-old right hander such an effective starter this season.

Wainwright’s numbers this season are for the most part actually very consistent to date with his work over his injury-shortened 2008 season:

2008 132 47 12 91 34 122 3.20 1.18 0.245
2009 137.1 46 13 123 51 126 3.01 1.29 0.243

One pair of numbers that jumps out at me is his strikeout and walk tallies. It has become immediately clear that Wainwright is relying upon the batted ball much less frequently than in 2008. FanGraphs’ PitchFX data offers some explanation, as it states that he has been throwing his off-speed pitches a solid three percent more often in 2009 than in 2008. This is probably a strong positive as they also assert that his fastball is giving up an additional 1.9 runs per 100 times thrown while his slider has improved by 1.5 runs/100 pitches and his curveball has improved by a whopping 2.38 runs/100 pitches to settle at an extremely impressive 3.77 runs/100 pitches fewer than league average.

So why has his curveball been so effective? We turn to a graph provided by Brooks Baseball to find out. The following is a plot of all of Wainwright’s pitches thrown against right-handed batters in yesterday’s game, seen from the perspective of the catcher:

This clearly demonstrates that Wainwright chooses to pound the outer half of the strike zone with his fastball (FT) and an occasional slider (SL) while dropping more than half of his curveballs (CU) low and away. FanGraphs indicates that opposing batters are swinging at his balls thrown outside of the strike zone 26.4% of the time in 2009 compared to 21.6% of the time in 2008. To top that off, they are actually only swinging at balls inside the strike zone 59.8% of the time, down from 61.9% in 2008. Clearly, he is keeping them guessing.

It doesn’t come as much of a surprise, then, that a pitcher who works the outside of the plate against right-handers doesn’t fare quite as well against left-handed batting. Wainwright holds a strong 3.53 K/BB ratio against righties but only a 1.75 K/BB ratio against lefties. Brooks Baseball again shows us why with a plot of Wainwright’s pitches against left-handed batters Saturday:

The natural movement of Wainwright’s curveball turns into left-handed batters, so the best he can do with that pitch is throw it low over the plate. Only once did he manage to throw his curve beyond the outside edge of the strike zone. You can see that he uses his changeup (CH) to work outside a bit, but against lefties he ends up throwing many more pitches on the inside where the batter can reach them when compared to his work against righties.

So to wrap up, Adam Wainwright has been as dominating as ever this year, due more than ever to a vexing curveball that keeps right handed batters on their toes.

Thanks go ironically enough to FanGraphs for their numeric data and Brooks Baseball for their graphs. Brooks Baseball has requested that anyone employing their graphs post a link to an auction seeking to raise money for ALS research, so I will gladly comply: SOSH Auction to K ALS

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Brian Walton

Brian Walton runs The Cardinal Nation and The Cardinal Nation Blog, covering the St. Louis Cardinals and minor league system.
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