Hisashi Iwakuma’s Loud Play

It may be because he is teammates with Felix Hernandez, who has been the No. 1 pitcher on ESPN’s player rater this season. It may be because he was already 31 years old before he threw his first pitch in the majors. It may be because he missed the first month of the season with a finger injury. Whatever the case, Hisashi Iwakuma has dominated batters very quietly this season. He deserves some attention.

Iwakuma’s sub-3.00 ERA this year is nothing new. Since he arrived in Seattle from Japan in 2012, Iwakuma has had an ERA of 2.87. That is just five points higher than Hernandez’s over the same time frame. It also places him in a tie for fourth in baseball over that period.

Best ERA, Starters, 2012-present
Minimum 400 IP
Name ERA
Clayton Kershaw 2.11
Johnny Cueto 2.56
Felix Hernandez 2.82
Chris Sale 2.87
Hisashi Iwakuma 2.87
David Price 3.00
Zack Greinke 3.01
Adam Wainwright 3.02
Cliff Lee 3.03
Jordan Zimmermann 3.09

Despite that consistent success, Iwakuma has a lesser profile than the other pitchers on the list. His 7.45 strikeouts per nine limit his fantasy potential relative to the likes of Clayton Kershaw and Hernandez, but they are comparable to Adam Wainwright’s 8.06 strikeouts per nine and Jordan Zimmermann’s 7.16 strikeouts per nine. Meanwhile, Iwakuma has dramatically reduced his walk rate, which sits at just 0.74 per nine this season. His 10.00 strikeouts per walk this season is actually the best in baseball.

Highest K/BB, Qualified Starters, 2014
Name K/9 BB/9 K/BB
Hisashi Iwakuma 7.45 0.74 10.00
Phil Hughes 7.99 0.81 9.82
David Price 10.00 1.28 7.81
Masahiro Tanaka 9.39 1.32 7.11
Felix Hernandez 9.60 1.56 6.16

Iwakuma may not have elite strikeout potential, but his ERA and WHIP are such that he could be considered a top 10 starter. Even without a start in April, Iwakuma has been a top 25 starter on the player rater this season, ahead of pitchers including Madison Bumgarner, Stephen Strasburg, and Anibal Sanchez.

To some extent, I understand the reticence of many to believe in Iwakuma’s success. He may be fourth in ERA since his debut in 2012, but he has also outperformed his FIP by more than any other starter in the time frame.

ERA-FIP Leaders, 2012-2014, Minimum 400 IP
Name Team IP ERA FIP ERA-FIP
Hisashi Iwakuma Mariners 441.2 2.87 3.65 -0.78
Jered Weaver Angels 468.1 3.13 3.9 -0.77
Chris Tillman Orioles 410.2 3.66 4.41 -0.75
Johnny Cueto Reds 421.1 2.56 3.31 -0.75
Kyle Lohse 2 tms 536.2 3.14 3.75 -0.61

Specifically, Iwakuma has had an 81.5 percent strand rate, which is the best in baseball since 2012. That is not dramatically clear of the field, but it is much harder to explain than the 79.4 percent and 79.3 percent strand rates of Johnny Cueto and Julio Teheran, who are second and first in pickoffs since 2012, and the 79.9 percent strand rate of Kershaw, who also picks off a lot of runners and is really, really good.

Iwakuma doesn’t pick off a lot of runners. He doesn’t induce a lot of double plays. His batted ball profile is ordinary. His team’s defense has been bad. There is no obvious reason he has so much success with runners on base, but he does. And now that he has continued that success into this third season, I believe he has earned our trust that it will continue. The strikeout ceiling holds him out of my top 10 starters, but he is in my top 15.




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Scott Spratt contributes to ESPN Insider as a research analyst for Baseball Info Solutions. He also writes for Pro Football Focus, and he is a Sloan Sports Conference Research Paper Competition and FSWA award winner. Feel free to ask him questions on Twitter – @PFF_ScottSpratt


3 Responses to “Hisashi Iwakuma’s Loud Play”

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  1. Fred says:

    Thinking about LOB%, what is Iwakuma’s windup like? As an Orioles fan, its very noticeable that Tillman’s windup is very similar to his motion from the stretch. I’ve been wondering whether having very similar motions from the windup and stretch can lead to better than expected performance with runners on base compared with pitchers who have two very different deliveries.

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  2. Choo says:

    Stylistically, Iwakuma has that little foot flick during his leg kick regardless of who/where is one base, but his timing differs greatly delivery vs. stretch. From the windup, he has a signature pause during his leg kick. From the stretch with a runner on first, he is much quicker. With runners on 1st and 2nd, he is somewhere in between but will occasionally use his quicker delivery to keep the lead runner honest.

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  3. Matt says:

    His strikeouts have really jumped over his last three starts. Based on his first strike percent, he could be ready for a spike in strikeout rate. His swinging strike rate has also been quite good for most of his major league career. I wouldn’t be surprised if he had better than an 8 K/9 the rest of the season.

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