How many times this past season did Aaron Rowand swing at a slider and miss completely?

Thanks to the magic (and nerdery) of PitchF/X we can answer that question. In 2009, Rowand swung at, and missed, the slider 63 separate times. Seems more than that, doesn’t it? For most of the season, the slider seemed to give Rowand a good bit of trouble. According to FanGraphs’ linear-weights pitch values, among qualified hitters in the majors, Rowand was worth -7.6 runs when hitting against the slider as compared to the average major league hitter against the same pitch. That placed Rowand as the 11th worst hitter in the majors last season against the pitch. Not an awful ranking, but one that indicates that Rowand could never get going against the pitch. If you’re wondering if Rowand has always struggled against the slider, it’s a mixed bag. The -7.6 runs in ’09 was a career worst ranking. It beat his previous low mark of -4 runs in ’08.

From 2002-2008 he has produced the following numbers against sliders: -3.2, 2.8, -1.7, -2.8, -1.4, 6.3, and -4.

Some highs (his 2007 with the Phillies) and lows (his recent struggles) but for the most part he’s been within a few runs of average. Further messing around with PFX tonight, I decided to plot all of the swings-and-misses that Rowand took in ’09 against the slider just to see what it looked like. Here’s the results.

I assume for a right-handed hitter, this is a pretty standard distribution. The slider that’s low and away seems to be the classic swing-and-miss pitch for RHB’s. Though, Rowand did miss a few sliders in the strike zone. To lay off the low and away slider it’s all based on split second pitch recognition. They say that you can identify a slider because of the “red dot” on the baseball caused by the spin of the seams. See dot, hit dot.

I also plotted sliders by called strikes and swinging strikes.

Green dots are called strikes, red dots are swings and misses.

If you’re wondering which hitter in baseball had the hardest time against the slider in ’09, using FanGraphs’ pitch-type values, it was Kevin Kouzmanoff of the San Diego Padres. His -16.3 runs against the slider was the worst for qualified hitters. By PFX data, he swung at the slider 82 times without making any contact. That’s nearly +20 swings and misses over what Rowand did.

For fun, I plotted his swings and misses to compare with Rowand.

Click to enlarge

Overall, looks pretty similar. There’s a tighter grouping of sliders in the bottom-right of the zone, but other than that, they look almost the same in terms of location. Kouz seems to go after the slider that’s away from him more than Rowand. Food for thought, I wonder how much variance hitters can have season-to-season against pitch-types? For example, Ryan Howard was the best in baseball against the slider this year with a score of +16.3 runs but that was after posting back-to-back seasons of -8.6 and -6.6 runs.