Making Sense of Jarrod Parker

Jarrod Parker wasn’t right early in the season. Through April, Parker had given up 43 hits in 29.1 innings, and carried a bloated 7.336 ERA. There were some analysts who started to wonder if there was something wrong with the 24-year-old. Just before worry could turn into legitimate concern, Parker pulled himself out of his funk. The turning point was a May 17 start against the Royals. Since that start, Parker has a 2.19 ERA over seven starts. That’s hardly a large sample, but it’s enough to put those April fears to rest. Much of Parker’s early struggles came from an inability to locate his fastball. While that issue hasn’t completely gone away, Parker has been able to survive by making a few tweaks to his approach.

Parker’s four-seam fastball continues to be somewhat of an issue. His inability to locate the pitch in 2013 is still present. Parker’s four-seamer has seen its ball percentage increase as the year has gone on, according to Through his first eight starts, the pitch had a 39.09 ball percentage. That’s actually gone up over his last seven starts, sitting at 40.48% during that period. Though he hasn’t fixed the problem, it doesn’t actually matter as much due to a change in his pitch selection.

Parker has relied on his four-seam fastball much less this year. The two biggest beneficiaries of this change have been his sinker and his slider.

Pitch Usage 2011-2012 Through May 10 May 17 – Present
Four-seam 37.39% 28.55% 21.27%
Sinker 25.99% 34.35% 37.97%
Slider 11.84% 13.04% 17.22%

Coming into the year, this didn’t seem like a bad change. Parker’s four-seamer was hit harder than any of his other pitches through 2012. Hitters had a .454 slugging percentage against the pitch, with eight home runs. His sinker was far more effective at keeping the ball on the ground, which should have helped him limit his home runs in 2013. That wasn’t the case early on. Parker’s sinker was clobbered in his first seven starts of the year. He gave up six home runs through seven starts, with an absurd .702 slugging percentage. Either Parker didn’t have a good feel for the sinker early on, or his neck injury was a bigger issue than initially reported at the start of the year.

Whatever plagued Parker early on hasn’t been a problem lately. The sinker has been dominant over Parker’s most recent stretch. He’s limited hitters to a .219 slugging percentage on his sinker over the last eight starts. He hasn’t allowed any home runs off the sinker. While he’s using the four-seamer less, it’s continued to get destroyed.

Parker’s slider hasn’t transformed into a much better pitch, but he’s learned that he can lean on it more often and not get killed. Parker was hesitant to throw the pitch to lefties last season, using it just three percent against them. He’s upped his usage in 2013, from seven percent in his first eight starts, to 13% in his last seven. Parker only tossed 53 sliders to left-handers last year, but was generally effective with the pitch. It’s remained a decent option against both righties and lefties even with the increased usage this year. The slider really hasn’t been a problem the entire season, but his ability to rely on it more often was a big development when both versions of his fastball had eluded him.

Now that Parker seems to have his sinker under control, things have been much better. Parker’s command issues haven’t been permanently solved, but he’s been able to offset the most pressing issues for now. Home runs also continue to be an issue, though that can be remedied by continuing to rely heavily on his sinker. A little over a month ago, it looked like Parker was heading for the surgeon’s table or the minors. But after making some slight changes to his approach, there’s reason to believe he’ll continue to be his old self going forward.

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Chris is a blogger for He has also contributed to Sports on Earth, the 2013 Hard Ball Times Baseball Annual, ESPN, FanGraphs and RotoGraphs. He tries to be funny on twitter @Chris_Cwik.

6 Responses to “Making Sense of Jarrod Parker”

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  1. d_i says:

    Average babip in starts before 5/17 = .338. Average babip in starts since 5/17 = .189

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  2. Forrest Gumption says:

    Just another case of “playing through” an injury with the usual terrible results. Injury heals, he gets back to normal.

    His ERA inning by inning is pretty funny this year though. Every other inning is good/bad/good/bad/good/bad/good

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  3. Sgt Hulka says:

    Interesting. What would you add to Parker in a deal for Bailey? Like a Rendon/Myers type?

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    • kevinguy says:

      I don’t think there is a very big gap right now between Parker and (Homer) Bailey – assuming it’s not Andrew. Bailey has more strikeout upside, but Parker has been extremely consistent and is less prone to blow ups. I think his strikeout rate will improve as well. I certainly wouldn’t give up a Rendon or Myers. There’s certainly not that sort of gap between the two, if much at all.

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  4. RTG says:

    Parker’s best pitch historically has been the changeup, and evidently it has been his second-most-used pitch since May 17, making up the ~25 percent of pitches not represented in the chart. My guess is that once the sinker started working and he started to use it more often, both it and the change got more effective. Do the stats bear out this theory?

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