A Last Look at First-Pitch Aggressiveness

Wrapping up my series on first-pitch aggressiveness I am ready to address the second question I put froward in Monday’s post: to see whether it first-pitch aggressiveness against good pitchers pays off. Before I do that, though, I want to address a suggestion from the comments section of Monday’s post who wanted to see Monday’s chart broken up by batter quality.

I took Tango’s suggestion:

Right, what the others have been saying. Chipper is a career .400 (wOBA) hitter. I’d rather see five charts with the breakdown at those levels:
.380+ hitters
under .290

Here are the z-swing rates for these five groups of batters for first pitches and subsequent pitches by pitcher xFIP. The color of the line indicates the group with the lightest gray the worst hitters and black the best. The dotted lines are for first pitches and solid for all others.

Sorry that the graph is a little cluttered, but that is the point. There is noclear relationship, if I had included the standard errors for these lines the five first-pitch ones would overlap completely and the five subsequent-pitches ones would as well. All five groups have pretty much the same swing rates and no clear trend depending on the xFIP of the opposing pitcher. So Jones’s first-pitch aggressiveness against good pitchers is unique compared to not only the average batter, but also compared to his peer group of very good batters too.

Ok now we can turn our attention to how this behavior affects the result of an at-bat. I break at-bats into one of four groups: those with first pitches in the zone and swung at, in the zone and taken, out of the zone and swung at, and out of the zone and taken. For each group I calculate the wOBA of the at-bat and plot against the pitcher’s xFIP. Color indicates whether the pitch was in the zone, black in the zone and red out. Line style whether the pitch was swung at, solid swung at and dotted taken.

First look at the first pitches out of the zone (red). There is a huge difference, no matter at the quality of the pitcher, in the result of at-bats when these pitches are swung at or taken. The difference between starting an at-bat 1-0 versus out-of-zone contact or starting 0-1 is great, even against poor pitchers. I think this goes a long way in explaining batter’s low swing rates on first pitches. Batters cannot tell for sure whether the pitch will be in the zone, and better to not swing.

On first pitches in the zone there is not quite as much difference, but the size of the difference expands as the pitcher gets better. So not swinging at a first pitch in the zone against a good pitcher results in a great deficit (versus swinging at it) than not swinging at a first pitch in the zone against a poor pitcher. This would suggest that swinging at first pitches more often against good pitchers is a good idea. But only if you have a good idea whether the ball will be in the zone or not, because the disadvantage of swinging at a first pitch out of the zone is just so great.

I think this is the reason Jones is well poised to exploit this difference and swing so often on first pitches against better pitchers. Few batters have his ability to swing at balls in the zone and not those out of the zone.

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Dave Allen's other baseball work can be found at Baseball Analysts.

25 Responses to “A Last Look at First-Pitch Aggressiveness”

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  1. Corey says:

    I would be interested to see what Pujols first pitch agressiveness would be. Early in his career he never swung at the first pitch but it seems that over the last few years his first pitch swing rate has increased. I may be wrong but that is how it appears.

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    • Steve K. says:

      Baseball Reference has first pitch swing percentages:

      2001 — 26%
      2002 — 25%
      2003 — 26%
      2004 — 25%
      2005 — 20%
      2006 — 19%
      2007 — 12%
      2008 — 18%
      2009 — 16%

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      • Bronnt says:

        Whoa-what changed from 2004 to 2007? Swing %’s cut in half over a 3 year period?

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      • Travis L says:

        @bronnt as these are unadjusted numbers, I would expect that pitchers simply stopped throwing him first pitch pitches in the zone.

        I can’t find that data on B-R, sorry.

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  2. Temo says:

    So Chipper is really smart and knows that taking strike 1 against a top pitcher is way worse than taking strike 1 against even an average pitcher. Also, he is able to exploit this because he knows with much greater-than-average certainty whether a pitch is a strike or a ball.

    But he obviously can’t “teach” this approach to hitters who don’t have his level of strike zone recognition. I think that goes a long way in explaining why great hitters don’t always become great hitting instructors.

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  3. Devon says:

    Awesome. Just awesome. This is when I love the stats. Chipper is instinctively maximizing his advantage without needing these graphs but they are so informative and could certainly aid other players. Fantastic stuff!

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  4. Jimbo says:

    Brilliant presentation.

    I’d be interested to see the top 20/bottom 20 lists for first-pitch discipline.

    Then I wonder how consisent and predictive that would be…

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  5. Bradley says:

    Excellent work, sir!

    What program makes those beautiful charts? Is that something Fangraphs does?

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  6. RMR says:

    Great work. I think this is an example of something I’ve always suspected: most players have developed their approach to hitting to maximize their success — even if they couldn’t tell you exactly how or why. Reds fans debated for years about whether or not Adam Dunn would be more successful if he swung more, particularly early in the count. This type of analysis would have been quite helpful..

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  7. MGL says:

    This is great stuff and it is going to take me a while to digest it and formulate some questions and comments.

    “So Chipper is really smart and knows that taking strike 1 against a top pitcher is way worse than taking strike 1 against even an average pitcher.”

    It is not WAY worse to take a pitch in the zone against a good pitcher. Only a little worse, as you can see from the width of the two lines at the left (good pitchers) and at the right (bad pitchers). That suggests that you want to be a LITTLE more aggressive on the first pitch against good pitchers, but not a lot, everything else being equal.

    That also suggests that Chipper’s strategy is NOT nearly optimal for an average hitter even of his caliber and strike zone recognition abilities.

    But, that doesn’t mean that it is not optimal for HIM. The only way to get an idea as to whether that extreme strategy that he uses is correct for HIM is to analyze HIS results. And even then, that will not yield a definitive answer, because we can never know what would happen if a batter used a different strategy that he uses, because he may not be “comfortable” with that strategy. For example, it is NEVER correct to always take the first pitch (across all situations), otherwise the pitchers will just throw a fastball right down the middle every time at a 0-0 count, but certain batters like to do that, such as Boggs. Who are we to tell them not to do that. Similarly, it is NEVER correct to always take a 3-0 pitch (across all situations), otherwise pitchers would also just throw a batting practice fastball right down the middle, but some batters, like Piazza (I think) just don’t like to swing at 3-0 pitches.

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    • Temo says:

      Ah, of course. There’s an opportunity cost to not swinging at a ball in the zone (ie, your performance for when you do swing at it).

      Good point.

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  8. Bronnt says:

    Geez, there’s a lot of data contained in those graphs to speculate about.

    Against most pitchers, it seems better to take strike 1 than to swing at pitch out of the zone, though against the best pitchers, that difference shrinks to nil. However, the sample isn’t entirely random, as the type of hitters likely to swing at the first pitch out of the zone are probably as good as the hitters who will take a strike in the zone on the first pitch. I say that because most hitters have a lower swing rate at first pitches, so those who’ll chase something out of the zone on the first pitch must not have great plate discipline. Those who can take a first pitch strike might be really confident in their ability to find another pitch.

    The best thing you can do in any at-bat appears to be to take a first pitch ball. Though against really poor pitchers, the difference between swinging at a pitch in the zone and taking one out of it shrinks significantly.

    Regardless, having good strike zone recognition is extremely important, and against good pitchers, the difference appears even more magnified.

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  9. Michael says:

    I would be interested to take one last look at first-pitch swing rates broken down by hitter wOBA. Are better hitters uniformly more aggressive in the way Chipper is? Are worse hitters floundering at everything?

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  10. garik16 says:

    MGL, that’s not correct. Whether Chipper’s approach is correct depends upon the % chance that the first pitch will be in the zone.

    If, as i suspect, better pitchers have higher in the zone on first pitch percentages, than his approach may be optimal.

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  11. MGL says:

    garik, “his approach” as in swinging more frequently against good pitchers? Yes of course. “His approach” as in swinging MUCH more frequently? No.

    You don’t need an analysis to know whether Chipper’s approach is “correct” generically, as in “for all similarly situated hitters.” The fact that he is the ONLY one to do it, even among good hitters with good pitch recognitions skills (presumably) tells you all you need to know.

    Do you think that everyone else (of his skill set) is wrong and he is right, or the other way around? Do you think that we can improve Albert, Mauer, Fielder, Braun, Manny, and all the other great hitters by having them approach first pitches like Chipper?

    Again, that does not mean that there isn’t something unique about Chipper (other than his basic skills that make him a great hitter) that makes his approach correct FOR HIM, but I sort of doubt that is true. Just because someone is a great hitter does not mean that they could not be better if they changed something about their approach.

    I would be willing to bet that if he shrunk the difference between how often he swings at first pitches against good and bad pitchers, that his wOBA would increase a point or two. I have no way of knowing that of course, and again, that would only true if he is “comfortable” with that new approach…

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  12. frug says:

    This makes me wonder what other kinds of “strategic hitters” there are out there (i.e. guys who adjust their plate approach at times that other guys do not).

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  13. Yet another good post. I posted a plug for your website at mine. Anyway, I think most people forget the point you are discussing.

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  14. Alfazedz says:

    Travis L says:
    March 10, 2010 at 6:54 pm

    “@bronnt as these are unadjusted numbers, I would expect that pitchers simply stopped throwing him [Pujols] first pitch pitches in the zone.”

    Usually, the first pitch is the best pitch Pujols sees, many of them being right down central. He just stands there looking as the ump yells “Strike”. Pitchers know he won’t swing at them so they use that to their advantage to get ahead in the count. On occasion he’ll swing at a first pitch (16% of the time), as a “surprise” to keep the pitchers honest. It doesn’t work. We get so aggravated with this. Of course this is Albert we’re talking about, and he can do what he wants.

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