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How Yusei Kikuchi’s rookie season compares to other Japanese pitchers’

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Kei Igawa where you at?

MLB: Detroit Tigers at Seattle Mariners Jennifer Buchanan-USA TODAY Sports

Yusei Kikuchi, the 28-year-old Japanese pitcher heralded as one of the Mariners’ best future-oriented signings of the most recent offseason, has largely struggled in his first year with Seattle. As it stands now, 25 starts into his MLB career, the deceptive lefty seems to have forgotten his deception in Japan. Following Tuesday’s outing in Detroit, Kikuchi owns a 5.56 ERA, 5.99 FIP, 1.52 WHIP, and averages three walks per nine innings compared to 6.77 strikeouts. All of that computes to -0.1 fWAR, which is fairly common for rookies, but more troubling considering the pedigree Kikuchi arrived with.

Before the 2019 season, FanGraphs pegged Kikuchi as the Mariners’ second-best prospect. The former Seibu Lion touted four straight seasons in Japan with a K/9 above 8, which included a masterful 2017 season in which he posted a 1.97 ERA, 0.91 WHIP, and 217 K’s in a career-high 187.2 innings. FanGraphs’ excitement over Kikuchi was centered heavily on an efficient arm action and a kitchen sink repertoire.

That repertoire, which includes a slider thrown roughly one-third of the time, has not played nearly as well as Seattle’s brain trust would have hoped. The pitch not only has negative value, it’s also getting walloped as MLB hitters get more used to it. For context: FanGraphs lists Justin Verlander’s slider at a league-best 20.8 runs above average, and Noah Syndergaard’s 2.2 clocks in at 31st. Kikuchi’s ranks 53rd out of 56 slider-throwers at -5.8.

Pitchers with similar profiles to Kikuchi generally use their funky mechanics and deceitful movement to make hitters chase bad pitches. That game plan has failed pretty categorically for Kikuchi in 2019. Kikuchi ranks 67th among 69 qualified starters in O-Swing%. In layman terms, there are only two pitchers in the league who force hitters to swing at pitches outside the zone less than the Mariner’s starter. Laying off the wiggly stuff to hone in on his fastball – which is also getting sledgehammered – has been a fruitful approach for hitters facing Kikuchi this year.

MLB: San Diego Padres at Seattle Mariners Jennifer Buchanan-USA TODAY Sports

While some Internet digging can tell us why and how Kikuchi has struggled, it can also point us to the early-career performances of other Japanese pitchers who came stateside. In looking at the rookie numbers of eight other high-profile Japanese signings (Yu Darvish, Kei Igawa, Hisashi Iwakuma, Hiroki Kuroda, Daisuke Matsuzaka, Hideo Nomo, Shohei Ohtani, Masahiro Tanaka), we get a better idea of how Kikuchi’s early days stack up to his fellow countrymen.

Let’s begin by comparing Kikuchi’s debut start – which carries the notable caveat of happening in Japan – with the eight others listed above. Kikuchi labored through 4.2 innings and 91 pitches at the Tokyo Dome but held the A’s to one earned run on four hits. Several others, including an infamous Yankee from the late 2000s, fared much worse in their first taste of The Show.

First MLB Start

Pitcher Age Year Opponent IP Pitches Strikes ER H K BB HR
Pitcher Age Year Opponent IP Pitches Strikes ER H K BB HR
Hideo Nomo 26 1995 @SF 5 91 51 0 1 7 4 0
Daisuke Matsuzaka 26 2007 @KC 7 108 74 1 6 10 1 1
Kei Igawa 27 2007 BAL 5 97 53 7 8 2 3 2
Hiroki Kuroda 33 2008 @SD 7 77 53 1 3 4 0 1
Yu Darvish 25 2012 SEA 5.2 110 59 5 8 5 4 0
Hisashi Iwakuma 31 2012 BAL 5 71 39 3 3 4 3 1
Masahiro Tanaka 25 2014 @TOR 7 97 65 2 6 8 0 1
Shohei Ohtani 23 2018 @OAK 6 92 63 3 3 6 1 1
Yusei Kikuchi 28 2019 OAK 4.2 91 58 1 4 3 1 0
*Iwakuma's first start came after 14 appearances out of the bullpen

Of course, one game is about the smallest sample size out there, but it’s still interesting to see how the excitement of an MLB debut affects a pitcher on the mound. Darvish said after making his MLB debut, “My mind and body were not on the same page. […] I threw so many one-hoppers to [catcher Mike] Napoli that I’m sure he’s all bruised up. I’m concerned about his health.”

It’s also interesting to compare the opponents tasked with spoiling each guy’s welcome party. Ohtani and Iwakuma are the only ones to make their firsts starts against teams that would make the playoffs that season, though Kikuchi could join that list as well. Dice-K debuted for a stacked Red Sox team that went on to win the 2007 World Series. The team in the other dugout was in the midst of nine straight losing seasons, and fanned 10 times that day against Matsuzaka, with future Hall of Famer David DeJesus providing Kansas City’s only run on a solo shot to right field.

Through the first half of their debut seasons, when numbers start to stabilize a little, we begin to see trends of how each pitcher’s workload, career path, and most importantly, success would play out.

First Half Numbers

Pitcher Age Year IP ERA WHIP K BB AVG OBP SLG
Pitcher Age Year IP ERA WHIP K BB AVG OBP SLG
Hideo Nomo 26 1995 90.1 1.99 1.07 119 46 .158 .271 .241
Daisuke Matsuzaka 26 2007 119.2 3.84 1.24 123 38 .242 .310 .383
Kei Igawa 27 2007 46.2 7.14 1.61 33 23 .275 .363 .519
Hiroki Kuroda 33 2008 105 3.43 1.2 62 29 .240 .294 .356
Yu Darvish 25 2012 102.2 3.59 1.36 117 53 .227 .330 .358
Hisashi Iwakuma* 31 2012 35.1 4.84 1.39 27 18 .242 .340 .453
Masahiro Tanaka 25 2014 129.1 2.51 1 135 19 .231 .263 .378
Shohei Ohtani 23 2018 49.1 3.1 1.13 61 20 .202 .285 .320
Yusei Kikuchi 28 2019 98.1 4.94 1.45 73 33 .281 .340 .488
*Iwakuma's first half numbers from his debut season were mostly as a reliever

Ohtani’s first half on the mound ended on June 6, about a month out from the All-Star break. Igawa, on the other hand, was so bad that the Yankees sent him down to High-A to work with special pitching instructors. He would eventually return on June 22 and make two more starts before the All-Star break, but was ultimately demoted again in late July and completely removed from the 40-man roster one year later.

With 25 starts now under his belt, we can paint a fairly clear picture of how Kikuchi’s maiden voyage compares to other Japanese pitchers’ of the last quarter century. Walks and homers have plagued Kikuchi a bit, but he can take solace in the fact that Nomo and Darvish (arguably the best Japanese pitchers ever) also had walk issues in their initial MLB seasons.

Kikuchi, to be clear, has been much worse than both of them, but the destruction he’s endured isn’t completely unprecedented. Of course, none of the other pitchers were introduced to the American game with a Super Ball in place of the normal baseball, either. Imagining Igawa’s numbers throwing a juiced ball in Yankee Stadium makes me incredibly fearful of a hypothetical situation.

Japanese Pitcher Rookie Seasons

Pitcher Age Year Starts IP ERA FIP WHIP K% BB% HR fWAR
Pitcher Age Year Starts IP ERA FIP WHIP K% BB% HR fWAR
Hideo Nomo 26 1995 28 191.1 2.54 2.89 1.06 30.3 10 14 5.2
Daisuke Matsuzaka 26 2007 32 204.2 4.4 4.23 1.32 23 9.2 25 2.9
Kei Igawa 27 2007 12 67.2 6.25 6.37 1.67 16.9 11.8 15 -0.4
Hiroki Kuroda 33 2008 31 183.1 3.73 3.59 1.22 15 5.4 13 3.3
Yu Darvish 25 2012 29 191.1 3.9 3.29 1.28 27.1 10.9 14 4.7
Hisashi Iwakuma 31 2012 16 125.1 3.16 4.35 1.28 19.5 8.3 17 0.9
Masahiro Tanaka 25 2014 20 136.1 2.77 3.04 1.06 26 3.9 15 2.9
Shohei Ohtani 23 2018 10 51.2 3.31 3.57 1.16 29.9 10.4 6 1.0
Yusei Kikuchi 28 2019 25 126.1 5.56 5.99 1.52 16.9 7.5 31 -0.1

By most measures, Kikuchi is having the roughest freshman year since Igawa, who was an objectively bad MLB pitcher. It seems unlikely that Kikuchi’s career will follow the same dismal path, but it makes his relative disappointment abundantly clear.

A hot finish to the end of the season could still provide a nice concealer on these blemish-filled numbers. The road to redemption will have to come from an improved slider and a fastball that avoids barrels, improvements that aren’t out of the question for a single offseason. Should positive results continue to elude Kikuchi, though, the Mariners will have a heaping plate of crow to eat. It is far too early to write the obituary on Kikuchi’s career, but when Kei Igawa is the closest comparison, this ominous beginning creates minor trepidation.