Clayton Kershaw: Like a Boss (of the Strike Zone)

I’m sure I’m accidentally quoting dozens of able writers and analysts when I state that at the heart of a baseball game lies the pitcher-batter confrontation — and that, at the heart of that confrontation, is a power struggle over rights to the strike zone.

If, in some kind of alternate reality, a batter (for whatever reason) weren’t permitted to swing, it’s very possible that Josh Tomlin or Doug Fister or some other control artist would dominate the game. If, in a different reality from that, there were no such thing as a base on balls — that a pitcher just needed, say, to get three strikes — then Aroldis Chapman and his 13.9% swinging-strike percentage would be incredibly valuable (until such a time as his arm fell off, that is).

As it turns out, batters are allowed to swing and there are such things as four-ball walks — and it’s for these twin reasons that pitchers must employ all manner of spins and changes of speed and menacing scowls to defeat their opponents within the strike zone (or, if possible, tempt them out of it).

Currently — and somewhat unexpectedly, I’d suggest — the pitcher most frequently winning this battle for strike-zone supremacy is Dodger lefty Clayton Kershaw.

Which, more on him in a second. First, a note on how we might measure strike-zone supremacy.

The criteria for the totally fictional title of Boss of the Strike Zone isn’t particularly complex — in fact, criterion, singular, is more accurate: one needs only to look at how often a pitcher is walking batters versus how often he’s striking them out. Traditionally, this has been measured by strikeout-to-walk ratio (K/BB); however, in a series of posts (blam, blam, blam) at his very astute blog, the very astute Tom Tango (along with the help of his very astute readers) has demonstrated that, really, taking the difference between strikeout rate (strikeouts divided by batters face, or K%) and walk rate (walks divided by batters faced, or BB%) — what we’ll call strikeout differential (or K-BB) — is more representative of a pitcher’s ownership of the strike zone.

What makes all of this particularly relevant is that, just two weeks ago, Dark Overlord of FanGraphs David Appelman added both K% and BB% to the site. This makes it possible to find a player’s K-BB really easily. And if one were particularly motivated, he could find the K-BB for all 108 qualified starters in the major leagues.

One, being so motivated, would discover that the top-10 pitchers by K-BB are as follows:

The presence of Roy Halladay on this list is decidedly not surprising. Same goes for Cole Hamels, Cliff Lee, and Justin Verlander: all are known for pitching masterfully and all have appeared here in previous seasons. But the presence of Kershaw at the very top of the list, I think, is surprising.

There has, of course, never been any doubting Kershaw’s raw stuff. He’s a lefty who sits at 93-95 mph with his fastball, owns a nasty slidepiece, and has averaged over a strikeout per inning through his first three major-league seasons. The problem, of course, has been controlling said stuff: over those same first three major-league seasons, Kershaw allowed 4.2 walks for every nine innings (11.1% BB). This season, those numbers have dropped to 2.36 and 6.6%, respectively.

At the same time, Kershaw’s K% has been rising slowly, from 21.3% in his rookie season of 2008; to 26.4% and 25.0% in 2009 and ’10, respectively; and now to his current (league-leading) rate of 28.6%.

What’s behind Kershaw’s improvement? The exact reasons for that are outside of the present author’s skill set. The hard slider that Daves Cameron and Allen discussed back in April appears to be an actual thing: not only does Pitch F/x say that the slider has been 2 mph faster on average than the one he’s thrown the last couple years, but it’s also been worth more per 100 thrown (3.93 runs) than ever before (last year’s 2.77 runs per 100 was his high).

Mostly, though, we might say that, if some pieces at FanGraphs are strictly analytical, others are designed to alert the reader to changes in this or that baseball-related narrative. Previously, the popular narrative regarding Kershaw has been something like “great stuff, hard time controlling it.” However, that narrative is changing. Clayton Kershaw is officially the Boss of the Strike Zone at the moment. Baseball fans should adjust their assumptions accordingly.




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Carson Cistulli occasionally publishes spirited ejaculations at The New Enthusiast.


48 Responses to “Clayton Kershaw: Like a Boss (of the Strike Zone)”

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  1. Feeding the Abscess says:

    Tyler Clippard and Koji Uehara both have SwStr% north of 17%. 17%!

    It’s not fair to compare relievers to starters, but here are Uehara’s K%/BB% the last two seasons:

    31.6%/2.6%
    35.5%/4.8%

    !!!

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  2. Christian says:

    Kershaw doesn’t eat… He feasts.

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  3. corey says:

    Brandon Morrow? Come on, the guy couldn’t hit water if he fell out of a boat.

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  4. Chris says:

    Like a boss is one of my favorite sayings, so I approve of this article!

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  5. mcbrown says:

    Zach Greinke says: “Just wait until I get a few more innings under my belt, Clayton.”

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    • Kevin Watanabe-Smith says:

      Precisely. Kershaw has been amazing but Greinke’s peripherals this season are unreal this season. He’s got 2.5% on Kershaw’s K%, xFIP and SIERA both love him (2.17 each), just can’t seem to go beyond 6IP this year.

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  6. thalooch says:

    ok, could someone help me out, what exactly is the formula for arriving at the k-bb numbers that we have here on the right?

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  7. FairweatherFan says:

    Well, I know that you didn’t really look at relievers, but Mr. Romo has a very impressive K-BB of 36.9.

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  8. AA says:

    …and you left out his best pitch. Uncle Charlie (thanks Vin)

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    • Bip says:

      His curveball definitely is no longer his best pitch. That slider is incredible.

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    • baty says:

      His finally developing a change up is a huge part of this. That was the pitch he needed and look out if/when it starts becoming a force.

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    • baty says:

      Kershaw’s pitch velocity differentials are very intriguing. You don’t see many lefties beating a hitter up in the zone with a fastball as often as Kershaw does…. a 20 mph drop to his curveball… and with a 10mph drop towards his slider from the fastball, he uses it in a similar way to how Lincecum uses his change up (when at his best). With two strikes it sees the dirt more often than it sees the strike zone. His slider might be the best out pitch in the game right now.

      In my opinion, there’s still more room for growth. His GB % is starting to climb and this should continue to happen with yearly drops in BB% from 13.6 to 9.6 to currently 6.8. He’s finally gaining command and it should continue to translate into dominating K and GB percent rates. The key is the change up though. If and when he sees a decline in velocity, he’ll need to flash that pitch at higher rates.

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  9. I agree with mcbrown: Greinke currently has 31.1 K% and 5.3 BB% giving him a 25.8 K-BB…this means Sir Zach owns the strike zone as soon as he picks up a few more inning (he’s already at 94 IP)

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  10. dcs says:

    —”Traditionally, this has been measured by strikeout-to-walk ratio (K/BB); however, in a series of posts (blam, blam, blam) at his very astute blog, the very astute Tom Tango (along with the help of his very astute readers) has demonstrated that, really, taking the difference between strikeout rate (strikeouts divided by batters face, or K%) and walk rate (walks divided by batters faced, or BB%) — what we’ll call strikeout differential (or K-BB) — is more representative of a pitcher’s ownership of the strike zone.”
    *********************

    I don’t think the term “more representative of a pitcher’s ownership of the strike zone” is the proper way to describe Tango’s finding–he simply found that the ‘difference’ correlates with overall effectiveness better than the ‘ratio’. I would argue that the ‘difference’ represents some combination of control of the strike zone plus stuff, and that is why it correlates better.

    This is, IMO, not just a semantic thing. The spread of BB among pitchers is about half that of K, per PA. So, it is twice as ‘difficult’ to get one fewer walk allowed than to get an extra K. But weighting them the same as in the ‘difference’ formula ignores that reality, while using the ratio captures it.

    It all comes down to what you want to measure, and how you verbalize the concept.

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    • Al Dimond says:

      Wouldn’t the right measurement for total effectiveness through strikeouts and walks be essentially the FIP formula, with the HR term removed?

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      • Al Dimond says:

        (Well, actually since FIP uses K/9 and BB/9 it’s not quite the same… and the real relationship between K%, BB%, and run scoring is non-linear, so any linear formula will break down for extreme cases… to be precise you’d need a run-estimator formula with batted-ball result ratios all held average, but at that point you’re beyond mental math).

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  11. Shaun Catron says:

    How many more innings until Greinke qualifies? Im guessing he would be #1 because of his ridiculous K/BB ratio

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  12. Stataholic says:

    I fail to see what is so special about Kershaw, it is obvious to even the most novice statistician that he is much more lucky than good. When his BABIP, xFIP, HR/FB and LOB% regress back into acceptable ranges this guy is league average, basically Jorge De la Rosa in a Dodger uniform.

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    • Shaun Catron says:

      probably the stupidest comment ive ever read.

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      • Stataholic says:

        so having a career .284 BABIP, 76% LOB %, 6.5% HR/FB rate and having your ERA ouproduce your xFIP isn’t getting lucky. Are you maintaining that Kershaw is able to control these ratios where other pitchers can’t. Unless he’s getting help from Jobu, he’s no different than any other pitcher once the ball leaves his hand.

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      • jim says:

        you’re an idiot, stataholic. look at his splits and how he’s improved every aspect of his game every season he’s spent in the majors, you fool. as the SIERA series demonstrated, high K pitchers can and should have lower BABIP and HR/FB.

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      • Stataholic says:

        I would hate to think that ones career had peaked at 21. Somehow a low K guy like Jurrjens can post luck ratios mirroring Kershaws but a guy like Hamels and Beckett can K batters but have unlucky ratios and be percieved as having down years or struggling thats whats laughable

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      • DD says:

        Statoholic – if you want to compare Becket with Kershaw, let’s do it, you already set the parameters:
        HR/FB rate – Beckett 9th of 108, 5.4% Kershaw 25th
        LOB% – Beckett 2nd of 108, 83.8% Kershaw 39th
        BABP – Beckett 1st of 108, .220 Kershaw 41st

        As you can see, Beckett is by far, in each case you cited, the extreme outlier compared to his peers. It stands to reason the guys who are the extreme outliers, not the guys closer to the mean, would be one ones we would expect to regress. I’m not positive, but I believe this is called “common sense”.

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      • Stataholic says:

        I was using stats from 2008 – 2011 so I had a larger sample than 20 starts

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      • Stataholic says:

        See how elite Beckett can be when he has Kershawesque luck on his side where in past years his HR/FB, BABIP, and HR rates have been well above average.

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      • Shaun Catron says:

        Beckett got lit up by the Royals today, I’d like to see what Beckett’s numbers look like a month from now.

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    • Ivdown says:

      This guy is an NL West fan, clearly. I’d be willing to bet Giants fan. Kershaw is average like Lincecum isn’t a Cy Young winner.

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  13. Duder says:

    lmao @ Stataholic.

    Kershaw is like 4 – 9 years younger than other elite starting pitchers in the majors. while his other contemporaries were in the minors, kershaw was posting back-to-back 4+ WAR seasons at the age of 21 and 22. the main issue most had about him going forward has already be cleaned up in his sometimes spotty control.

    he’s having a historically great season considering how young he is. seriously, when’s the last time a 23 year old put up a 6+ WAR season?

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    • Stataholic says:

      it’s easy to be elite with a .283 BABIP, 74.7% LOB % and a 7% HR/FB rate, all the things you look at for a pitcher doing better than he should. He’s actually throwing even less strikes than last year, 51.5% down to 48%, so there’s the improved control mirage blown to pieces by the facts.

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      • drifter909 says:

        Remember STATAHOLIC, those numbers aren’t in a vacuum. You have to compare them with other pitchers.

        a 74.7 LOB% puts him 70th out of 108 qualified starters. so 69 starters have a lower percentage…technically this means he’s been slightly “unlucky” compared to other pitchers according to this stat.

        Even his .283 BABIP puts him 40th out of 108, not super “lucky” as you claim. The HR/FB ratio is a bit low, 25th out of starters, but a quick look at the SIERA articles explains why both the BABIP and HR/FB ratios of high strikeout pitchers should be lower compared to other pitchers.

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      • Ivdown says:

        If you haven’t noticed, which, screw it, i know you haven’t, Kershaw, AT EVERY LEVEL, has been good at:
        1. Not allowing a lot of hits
        2. Not allowing a lot of home runs
        3. Striking out insane amounts of people

        He’s been a bit wild in his career, but from the middle of 2010 till now he’s found out how to harness his stuff and control it to be come absolutely elite. Good like finding more than 2 percent of the population that would be idiotic enough to agree with your “findings”

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      • Bip says:

        Doing better than he should? His ERA is higher than both his FIP and xFIP this season.

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      • Nathaniel Dawson says:

        Drifter, a high LOB% is a good thing for a pitcher, a low LOB% isn’t. Whether by dint of luck or skill, Kershaw has been better than the average pitcher at not allowing baserunners to score. Of course, he’s a better than average pitcher, with a very low OBP, so you would expect that.

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  14. Sam says:

    Another interesting way to measure “mastery of the strike zone” might be to look at the pitcher’s plate discipline numbers. If you look at Kershaw for example, you see that he is at a career low as far as pitches in the zone (Zone %) and at a career high with regards to Swing %. He also is walking many less batters than ever before. These numbers–less pitches in the strike zone, but more swings, and less walks–are descriptive of the way in which Kershaw is mastering the strike zone, and suggest increasing command, and greater control of what pitches batters swing at.

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    • DD says:

      What it suggests is his pitches are generating a high percentage of swings OUTSIDE the zone with limited contact, and lo and behold, his career high 32.4% O-Swing % is well above league average, while his O-Contact % is well below league average, at 60%. It’s not that he has improved his control by throwing his pitches more for strikes IN THE ZONE, but he’s getting strikes OUTSIDE the zone better than almost everyone else.

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      • Bip says:

        His improved control is what is allowing him to do that however. I’m not sure if that’s what you’re saying or not, but yeah, I just wanted to add that.

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      • DD says:

        Bip, I’m sure he has better control, but basically he has found a way to get guys out, increasingly by strikeout, without throwing more pitches in the zone. He’s figured out how to get guys to stretch the strike zone, which generally means he’s figured out “how to pitch”, instead of just beating guys with stuff. Part of that is likely better control as well.

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      • baty says:

        If you take a look at his games, you’ll see that that’s by design. He’s more consistent than ever with how he misses the zone with that slider in contrast to a couple of years ago when hitters were flailing at pitches all over the place. As an example, on a regular basis you’ll see the catcher end up with the ball in his glove on the ground when he’s looking to get a swing and miss for strike 3. He’s found the right time and location to throw that pitch. To compliment that, he can show the fastball up to shoulder height. He’s learned how to toy with hitter discipline.

        In my opinion pitchers with dominating stuff and relatively solid command can create a larger perceived strike zone by a hitter. For a guy like Kershaw, you don’t have to live in the strike zone with your pitches, but figure out ways to stretch a hitter’s perceived strike zone to a degree that that hitter can’t handle with success. It’s not to say that hitters will continue to react this way to Kershaw throughout the duration of his career, but it works now.

        What can make him a true pitching great will be his ability to adjust his command tighter and tighter to the edges of the strike zone as hitters start to learn how to lay off those pitches.

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      • Bip says:

        “What can make him a true pitching great will be his ability to adjust his command tighter and tighter to the edges of the strike zone as hitters start to learn how to lay off those pitches.”

        It’s interesting that you say this, because during one of his last starts, his complete game against the Padres, there were a couple of times where the batter worked a full count partially by laying off his slider, and both times he threw a slider into the strike zone for a called strike three. If that’s not “pitching” then I don’t know what is.

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  15. Sam says:

    Agreed–he isn’t throwing more pitches in the zone. He’s just getting more guys to swing at pitches outside it. My argument if I have one is that this amounts to a mastery of the strike zone. The strike zone only matters to a pitcher to the extent that throwing pitches in the zone helps the pitcher avoid walks. I think that the fact that Kershaw is avoiding walks by throwing more, and presumably better, pitches outside the strike zone exemplifies the mastery of the strike zone he has shown this season, and that Cistulli is talking about.

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  16. Bip says:

    I like that Kershaw is so good that in order to be a detractor, one has to use troll logic like Stataholic.

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  17. Matt says:

    Stataholic your just once of those losers who predicted Kershaw to be a bust since his rookie year and can’t accept you were wrong, So you try and use anything you can to try and make it look like Kershaw’s a fluke so you don’t feel stupid.

    Hell even Lincecum said Kershaw hasn’t even peaked yet and ESPN said Kershaw has actually been somewhat “UNLUCKY”. So how can Kershaw be lucky when he’s been unlucky? Let me guess you know more about stats than the “experts” and “scouts”. How didn’t you get a job as a player analyst if you know so much more than scouts and experts?

    You should learn that the best way to judge a young player is to follow his trends. I’ve been telling people since day one it’s not all about his control, it’s about him improving on it that matters most. His WHIP fell each year meaning each year he gained more control and now you have what stands for you today, the best strikeout pitcher in baseball and a guy at 23 already being mentioned for the NL CY Young.

    But every year you have a guy like Stataholic come out and call Kershaw a bust or a fluke. It’s too bad they can’t delete their own comments.

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    • Shaun Catron says:

      Its all about idiots like Stataholic and their injured egos.

      Checklist of reasons Stataholic resorts to trolling like this:

      1) He predicted Kershaw as a “bust” when he was a rookie and hes butthurt that Kershaw is improving drastically every season

      2) He passed over Kershaw in his fantasy draft for Ubaldo.

      3) Hes craving attention, best way to get attention is to make a ridiculous statement to get replies.

      4) Hes just retarded.

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  18. CanMan says:

    Kershaw is getting ahead in the count which makes his slider more effective leading to a higher O-Swing%. Looking at 2011 vs 2008-2010 his percentage of 0-1 counts is 51.8 vs 50.1% and OPS of 0.413 vs 0.498
    1-0 35.0 vs 39.7% and 0.754 vs 0.772
    0-2 22.2 vs 22.3% and 0.121 vs 0.345
    1-2 31.6 vs 33.7% and 0.350 vs 0.400

    When he is getting ahead, his control has improved enough that if they do make contact it isn’t doing much damage.

    Comparatively for 2011 Roy Halladay
    0-1 52.6% and 0.461
    1-0 33.7% and 0.691
    0-2 24.4% and 0.374
    1-2 29.1% and 0.352

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