Potential Starting Pitcher K% Surgers

Last week, I published the results of my expected strikeout rate study. I used the looking, called, and foul strike rates data from Baseball-Reference.com. It is important to understand that the regression formula I concluded with is meant to estimate what the pitcher’s K% should be given his different strike rates. This is not meant to be predictive. Instead, in smaller sample sizes, it might be a more accurate picture of the pitcher’s true strikeout ability so far, which would then help shape your projection of him going forward.

With that said, here are the top 10 pitchers whose xK% is higher than his K%.

L/Str S/Str F/Str K% xK% Diff
Lucas Harrell 34% 10% 25% 11.9% 16.5% -4.6%
J.A. Happ 29% 13% 32% 17.3% 21.7% -4.4%
Scott Diamond 31% 11% 25% 10.9% 14.5% -3.6%
Jeremy Hellickson 28% 18% 26% 18.7% 22.2% -3.5%
Hiram Burgos 31% 13% 24% 13.0% 16.5% -3.5%
Clayton Richard 26% 13% 27% 10.1% 13.5% -3.4%
Philip Humber 28% 15% 21% 9.7% 13.1% -3.4%
Bud Norris 27% 16% 26% 14.9% 18.1% -3.2%
Pedro Hernandez 27% 12% 30% 12.8% 16.0% -3.2%
Juan Nicasio 28% 12% 31% 15.0% 18.1% -3.1%
Unweighted Population Avg 28% 15% 27% 19.1% 18.9%

This is not a very exciting list as it includes lots of low strikeout guys. However, there are some interesting names that are worth discussing. Oh, and stats are as of Saturday, so they don’t include any of yesterday’s starts like Hellickson’s.

Last season, Lucas Harrell enjoyed a rather surprisingly solid rookie campaign. His extreme ground ball ways offset mediocre control and a below average, though still respectable, strikeout rate. But his skills have taken a dive this year, as he’s actually walked more batters than he has struck out. The extremely low Zone%, which is down from last year, supports the worse control. If there’s any glimmer of hope, it’s that he’s getting a ton of looking strikes and by this formula at least, should have a significantly higher strikeout percentage. Still, it won’t really matter if he continues to walk over five batters per nine.

Scott Diamond came out of nowhere last year for the Twins, inducing lots of ground balls and exhibiting sterling control. The lack of strikeouts limited his fantasy value though. That strikeout rate has been even worse this year, but it could perhaps get better. And although his strikeout rates in the minors were never great, they certainly suggested better than what he has posted so far. A strikeout rate above 5.0 would give him value in AL-Only leagues.

There’s Jeremy Hellickson again on another bad luck list. Who woulda thunk it after he has been one of the luckiest pitchers in baseball the past couple of years based on his SIERA-ERA differential? His strikeout percentage is already up a bit from last year, and xK% is suggesting it should be even higher. After yesterday’s start, his ERA now stands at 5.59 versus a 4.14 xFIP, so he clearly hasn’t been as fortunate as in years past. Of course, a 4.14 xFIP isn’t exactly good to begin with and really would only provide value in AL-Only leagues. When I last discussed Hellickson, I said I wouldn’t bother with him in shallow mixed leagues, because even when his luck neutralizes, he’d still need the continued good luck of recent seasons to have value. My opinion hasn’t changed, though the high xK% is at least encouraging. It’s enough to recommend a buy low attempt in AL-Only leagues.

Bud Norris has seemingly experienced more bad luck than good during his career, as his defensive support has been sub-par. The move to the American League for the Astros figured to kill any rebound potential he had, but of course now the luck pendulum has swung the other way, as he sports a 3.39 ERA versus an ugly 4.80 SIERA. Though we would have expected the strikeout rate to decline, it’s a surprise it has come down this far. Luckily for Norris owners worried about his ERA regressing in the face of poor skills, his xK% suggests he should be posting a much better strikeout rate. With below average control and a league average fly ball rate, he’ll have to improve that strikeout rate quickly, otherwise that ERA is headed north of 4.00.

Here are the rest of the pitchers whose xK% is higher than his K%.

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Mike Podhorzer produces player projections using his own forecasting system and is the author of the eBook Projecting X: How to Forecast Baseball Player Performance, which teaches you how to project players yourself. His projections helped him win the inaugural 2013 Tout Wars mixed draft league. He also sells beautiful photos through his online gallery, Pod's Pics. Follow Mike on Twitter @MikePodhorzer and contact him via email.

15 Responses to “Potential Starting Pitcher K% Surgers”

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  1. Doc says:

    Great piece.. one question though. Hector Santiago is not on the list, and I’m curious as to why. After you posted the first xK% piece a week ago I attempted to make my own list, just as a funzies test. Everything I have done matches up with yours except for Santiago.. curious, is there is a reason he’s excluded?

    I’m not saying he should or shouldn’t be on the list, but wanting to better understand what the exclusion factors might be.

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    • Doc says:

      Nevermind.. answered my own question. Looks like a week or so ago he was moved back into the bullpen. I thought he was still starting.

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      • That doesn’t explain it as he was still on my list. Maybe it depends when we ran the stats? I have him with an xK% of 26.3% vs an actual K% of 26.7%.

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  2. bsball says:

    Lots of Astros near the top of that list.

    And Happ was an Astro last year.

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  3. Giovani says:

    Damn. Great research, too bad it yielded a crop of players that are generally unownable in mixed leagues.

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    • Yeah, well you had to assume this was going to be the case. The guys lowest in a metric have prob been a bit unlucky, while the guys who are best have probably been a bit lucky.

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  4. rbt says:

    Why do I have a sneaking suspicion that, if you did this for previous years, you would find that Hellickson’s xK% is always higher than his K%? He just seems like that kind of pitcher.

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    • Yeah, that’s possible. He underperformed last season and the year before as well. There are always going to be outliers, and that doesn’t necessarily mean they lack a skill, but that some pitchers are going to consistently be on the extremes by dumb luck alone.

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  5. dacure says:

    Really hope Cashner gets up to at least that 18.5 you expect. Hes been a bit of a disappointment

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  6. Rufus says:

    Are you assuming the effects are all linear? It does seem biased toward low-K pitchers. I do agree with your point on those pitchers being a little unlucky, but I think the bias in your numbers is well beyond that. Have you looked to see if previous xK% has any predictive value, controlling for actual K%?

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    • I did test out other curves, including exponential and logarithmic, and both yielded worse results than linear. I have not looked at the predictive ability, but I think someone else did in the comments of my original article.

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  7. Brian says:

    “This is not meant to be predictive … help shape your projection of him going forward.”

    … what?

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    • Meaning it’s another historical data point from which to develop your projection. Instead of using previous K% marks to forecast future K%, you would use previous xK% marks to forecast future K%.

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  8. Paul says:

    I can’t wrap my non-statistical mind. That is all, carry on.

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