Touching Bases April 22, 2010
Clusters in the Outfield (Part 2)

Last week in this very space, I used cluster analysis to try to quantify a hitter's spray chart. Commenter "Nightfly" asked, "Are the sample sizes for switch-hitters large enough to run a comparison of, say, Victor Martinez against himself, from each side of the plate?" So instead of comparing hitters to each other as I did last time, I'm going to juxtapose players against themselves. I ran the numbers to see which switch-hitters had the biggest gap between cluster centers, grouping by handedness. It turns out, Carlos Beltran is a pull hitter from both sides of the plate, which forces outfielders to shade five yards in either direction depending on whether he's batting righty or lefty. And to answer your question, Nightfly, no, Victor Martinez cannot throw out baserunners.

I changed the color scheme and symbols of the graph at the suggestions of commenters Studes and Alex, and as always, I'd appreciate any advice on how to improve the visuals provided.

That outfielders position themselves differently based on the batter's handedness is intuitive, but what other more subtle clues might improve outfielder positioning? Rich Lederer and commenter Fat Ted suggest I incorporate PITCHf/x data into my analysis.
For the upcoming analysis, I'm going to adhere to Peter Jensen's advice that I only look at balls that were caught by outfielders which improves the accuracy of the data but limits the sample.

First, I looked at how batted ball location fluctuates based on pitch type. It turns out that an outfielder only has to move several feet in general if he knows whether a fastball (two-seam, four-seam, cut) or an off-speed pitch (curve, slider, change, split, knuckle) is coming.

Juan Rivera, a right-handed batter, is one player who really gets around on off-speed pitches.

Meanwhile, Miguel Montero, a left-handed batter, nearly broke my clustering algorithm with his inability to pull fastballs. A visiting right fielder might fare just as well turning balls in play into outs by positioning himself in the Chase field pool when Montero is gearing up for a fastball.

I also looked at patterns dealing with pitch location by splitting the plate into halves. In addition to the fact that batters tend to go the other way with outside pitches and pull inside pitches, Balls on the outer half are also driven slightly farther than balls inside

Some hitters, like Jacoby Ellsbury and Ian Kinsler, can't drive inside pitches the other way with authority, which I imagine would be useful information to outfielders.

I have not thought about it too much with respect to your analysis, but only using balls that are caught is really problematic with respect to OF positioning, as that sample of balls is going to be dominated by lazy fly balls and contain few line drives. I would think that most batters will hit their line drives to different parts of the field than their lazy fly balls. Whether that varies from batter to batter, I don't know.

Inside, outside, USA!

Nice article.

thank you for helping out us colorblind readers!

Very good work. I especially like the charts based on pitch type. But I can see a problem with positioning outfielders based on what they expect to be thrown - a savvy hitter could be tipped off on the pitch based on where the defense is going. Putting a guy five steps to the left isn't helpful if the hitter uses that information to homer off a pitch he knows is coming.

Then of course you'd start getting into a football-style "disguised coverage" where the defense may shade for the wrong pitch in order to help fool the hitter, and so on.

Surprised that Beltran was the only guy you had a good sample size for. Do the other guys just not show a lot of difference in where the ball goes?