Thursday, January 30, 2014

What Happens When a Pitch is Thrown, Part 4 - Hey Batter Batter

We've established that for pitchers, throwing strikes is good, but getting strikes, from a combination of pitching in the strike zone and inducing swings outside the zone, is better. So let's find out whether the opposite is true for hitters: Do the best hitters avoid strikes, especially outside the strike zone?

When we looked at pitchers, we evaluated them based on ERA, WHIP (baserunners per inning), and percentage of batters getting strikeouts, walks, and home runs. For batters, let's keep the last three, but instead of the pitcher-oriented ERA and WHIP we'll use batting average, on base percentage, and slugging percentage.

Before I start, let me explain one tweak I did to the data: For pitchers, I included every pitch thrown in the majors last year. For batters, I'm going to exclude plate appearances by pitchers. I'm doing this for two reasons. First, pitchers are remarkably terrible hitters. They batted .132 with a .164 on base percentage and .169 slugging percentage last year. No position players come close to those numbers. Second, they screw up my analysis of balls and strikes. In looking at the numbers, I discovered there are two strategies when a pitcher's at the plate:

  1. Throw everything in the strike zone, then laugh derisively as they helplessly flail away.
  2. Throw everything outside the strike zone, then laugh derisively as they helplessly flail away.

That means that pitchers' at bats make batters who get a lot of pitches in the strike zone, and those who swing at a lot of pitches outside the strike zone, appear worse than they otherwise would be. So I'm excluding them. In terms of numbers, that means I'm ignoring 19,171 of the 709,916 pitches that were thrown last year. Given that that's only 2.7% of the total, I don't think we're missing much.

How are strikes and batting performance related? We'll start by looking at all strikes: pitches in the strike zone and pitches outside the strike zone at which the batter swings. We're checking to see whether batters with a lot of strikes do poorly. I ranked all batters by percentage of pitches to them that were strikes, and divided into ten groups. Group 1 got the fewest strikes, Group 2 the second fewest, Group 3 the third fewest...you get it. Group 10 had the highest percentage of strikes. Here's how they did:
     Group   BA   OBP   SLG    K%    BB%   HR%
       1   .254  .361  .433  21.1%  13.6%  3.4%
       2   .266  .353  .438  19.6%  11.1%  3.2%
       3   .256  .332  .404  19.3%   9.5%  2.5%
       4   .259  .332  .421  20.6%   9.3%  3.0%
       5   .267  .332  .431  19.2%   8.4%  3.0%
       6   .260  .319  .399  18.8%   7.6%  2.4%
       7   .255  .309  .381  17.8%   6.8%  1.9%
       8   .249  .301  .382  18.5%   6.3%  2.4%
       9   .252  .298  .383  19.5%   5.4%  2.2%
      10   .252  .288  .371  19.2%   4.0%  1.9%

Three reactions to this list. First, if you ignore batting average (which you should, since on base percentage and slugging percentage, as I showed, are better tied to run production), the relationship still holds: the more strikes a batter gets as a percentage of pitches, the worse the batter performs. It's not a flawless relationship, but it's good enough. Second, the batters who get the fewest strikes have the best home run percentages. Remember how that's not true for pitchers. But you can imagine a patient hitter like Joey Votto or Mike Trout or David Ortiz (they're all in Group 1) picking through pitches, waiting for one he can drive. Third, and this is counter-intuitive, the batters who get the lowest percentage of strikes nonetheless manage to strike out more often than anyone else. More on that in a bit.


How are pitches in the strike zone and batting performance related? Remember that pitchers who got more pitches in the strike zone did better than pitchers who didn't. The opposite for batting should be that batters who get the fewest pitches in the strike zone should do better than batters who don't. Here are the numbers:
     Group   BA   OBP   SLG    K%    BB%   HR%
       1   .258  .332  .438  21.6%   9.2%  3.5%
       2   .260  .328  .437  20.3%   8.5%  3.6%
       3   .257  .327  .408  18.6%   8.8%  2.7%
       4   .263  .333  .426  19.8%   9.1%  3.0%
       5   .255  .326  .399  19.9%   8.7%  2.5%
       6   .258  .320  .393  19.6%   7.6%  2.3%
       7   .267  .330  .415  18.9%   8.0%  2.5%
       8   .249  .308  .387  19.5%   7.3%  2.4%
       9   .255  .314  .370  17.8%   7.0%  1.7%
      10   .247  .301  .358  17.5%   6.5%  1.7%

Yes, the relationship holds, though it's not super strong. But hang on, think about it...this is kind of a trick question. Throwing balls into the strike zone is skill. Some pitchers possess it in greater quantities than others. But a batter getting pitches in the strike zone...not a skill. They're just standing there. Unless they get into an extreme Rickey Henderson-style crouch or something, there's nothing a batter can do to influence how many pitches go into the strike zone. Except, of course, by being good. Pitchers are going to pitch a lot more carefully to a slugger than a utility infielder. As a result, we should expect the very best hitters to get the fewest pitches in the strike zone. The table above illustrates that that's how it works. Groups 1 and 2 include guys like Giancarlo Stanton and Paul Goldschmidt. Group 10 has Clint Barmes and Pete Kozma

How are swings at pitches outside the strike zone and batting performance related? Strikes are the sum of pitches in the strike zone and pitches outside the strike zone at which the batter swings. For batters, getting pitches in the strike zone isn't a skill, but not swinging at pitches outside the zone is. Do batters who don't swing at pitches outside the strike zone do better than those who do? As usual, Group 1 represents the 10% of players who swing the least frequently at pitches outside the strike zone, and Group 10 represents the 10% who swing the most:
     Group   BA   OBP   SLG    K%    BB%   HR%
       1   .249  .342  .391  20.0%  11.6%  2.4%
       2   .262  .346  .436  19.1%  10.7%  2.7%
       3   .256  .331  .399  18.4%   9.5%  2.4%
       4   .256  .324  .396  19.3%   8.5%  2.3%
       5   .254  .322  .397  19.7%   8.4%  2.5%
       6   .256  .320  .412  19.1%   8.0%  3.0%
       7   .260  .314  .392  17.8%   6.8%  2.3%
       8   .264  .323  .426  20.4%   7.3%  3.0%
       9   .255  .301  .395  19.4%   5.6%  2.5%
      10   .257  .298  .406  20.3%   4.8%  2.8%

Certainly, the batters who swing don't swing at pitches outside the strike zone have a better on base percentage, because they walk more. But they don't appear to strike out less, hit with more power, or hit more homers.

So we've got a paradox: Good pitchers get batters to swing at pitches outside the strike zone, but swinging at pitches outside the strike zone doesn't appear to hurt batters other than to limit their walks. Why is that?

I think the answer is that good hitters have a sweet spot, and if the sweet spot is outside the strike zone, so be it. Group 1 here--batters who don't swing at pitches outside the strike zone--include bat-control guys who don't have a lot of power, like Marco Scutaro and Nate McLouth. Group 10 has several hitters who hit the ball hard but swing at most anything, like Mark Trumbo and Adam Jones. And All-Stars like Robinson Cano, Carlos Gonzalez, and Freddie Freeman swing at an above-average number of pitches outside the strike zone as well. 

So let's reiterate the paradoxical conclusion: Good pitchers get batters to swing at pitches outside the strike zone, but swinging at pitches outside the strike zone doesn't appear to hurt batters other than to limit their walks. Seems to me that if you don't like watching strikeouts, there's nothing to suggest things are going to get much better.


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