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Yusei Kikuchi is mixing the old with the new

Chicago White Sox v Seattle Mariners Photo by Steph Chambers/Getty Images

This is a crucial year for the Seattle Mariners and Yusei Kikuchi. After 2021, Seattle will have to decide whether to commit to a four-year club option for $66 million to lock him up through 2025 at an average of $16.5 million per year. That’s almost exactly the rate Mike Leake secured in free agency prior to 2016. It could be a great deal, or an unnecessary use of funds, and if Seattle declines the deal, Kikuchi gets a player option for 2022 at $13 million to boot. The entire situation is complicated enough, but Kikuchi’s inconsistency has thickened the plot into what we call a yes-brainer. Fortunately, in 2021, our first two looks at Yusei have been plenty encouraging, as he’s embraced change yet again, but kept what’s worked.

Here’s Yusei Kikuchi, at the zenith of his leg lift, every year of his Mariners career.


A few things stand out to the pitcher in me. The hands, the leg lift, and for good measure the back leg (aka the plant leg or drive leg). One of the beautiful things about pitching is that there are so many ways to get good results, and the growth of video and technological quality and availability has increased knowledge of things that work well or could be tweaked for improvement. Some things, however, remain rather universal.

One such mainstay is simple: the more repeatable your motion, the better outcomes you’ll have. Kikuchi has tinkered with his craft his entire career, earning eyebrow raises at times in Japan and encountering challenges in MLB. His double-pump motion was a fascination when he first arrived stateside, and had even earned questions from umpires back in NPB. Between the myriad of adjustments including a different ball, personal tragedy, and an effort to implement every little change or tweak proffered, however, he had a disappointing 2019. Here’s a reasonable average pitch from that debut campaign:

Nothing horrific, but what stands out in many of his 2019 clips, at least at the level of data available to me, is when his hands separate. As shown in the screenshots at the top of the article, Kikuchi’s hands are high when his leg lifts to its apex, something you might see from Clayton Kershaw, hardly a damning characteristic. But the double pump seems to alter his timing somewhat, as his hands break upon the second pump and begin to descend while his leg is still moving upward. I’ve done a cursory review of video and scoured my memory, and while there’s no doubt examples of this sort of two-way movement in other motions, it tends to go against the goals of both repeatability and getting all of the pitcher’s movement and energy flowing in the same direction and towards the point of release. It is not a shock, between this and the multitude of adjustments being made from start to start that Kikuchi’s results were as inconsistent as even his velocity and movement.

Prior to 2020, Kikuchi was able to get many features smoothed out and simplified, and the results, while less pronounced in his 5.17 ERA through 47.0 innings and nine starts, were underlain by huge strides in process and expected outcomes. His Fielding Independent Pitching (FIP) was a mere 3.30, good for 25th in MLB in the shortened season. His average fastball velocity rose from 92.6 to 95.1 mph, moving from average to elite as a starter. His K% rose from 16.1% to 24.2%, now above-average instead of well below. Even with a slight uptick in walks, hitters saw their average against him fall from .293 in 2019 to .236 in 2020. He was better, and there was plenty of reason.

From Ryan Divish at the Seattle Times:

Beyond the sabermetric data, there was also the MLB Statcast data measuring Kikuchi’s velocity and stuff on his pitches that showed drastic improvement. After consulting with Driveline Baseball in Kent and Mariners pitching coaches after the 2019 season, Kikuchi cleaned up his mechanics and shortened his arm swing in an effort to resuscitate the inconsistent velocity and stuff. In his first season, he was a mechanical mess, trying to implement every suggested change or tweak given to him. He would change from start to start and even inning to inning. By the end of that first season, he’d lost any semblance of his original mechanics and his identity as a pitcher.

So lets see 2020 Kikuchi:

No double pump, an easier motion, and in fact a higher leg kick that still goes up a bit as his hands break. But it’s easy to see how this might be more impactful - the energy generated is smooth and Kikuchi looks explosive with less labor than 2019. Still, the uptick in walks and occasional lapses in command hurt the lefty. While he was seemingly in better physical shape despite not being a “hamster”, Kikuchi noted the lack of execution at times in regards to his mental focus as a point of improvement for 2021.

Kikuchi’s goals this past offseason mirrored Servais’ goals. “Gain more control of all my pitches, more command and to simplify my mechanics,” he said. But there was another aspect to it. “I worked on the mental side of the game,” he said. “If I were to just have confidence in all my pitches, being able to throw all my pitches in any count. Command often leads to confidence. That was my main focus.”

That’s something that could account for his leading MLB in 3-0 counts last year and being third-to-last in first-pitch strikes. Through two starts this year, Kikuchi has carried through the sharper and harder stuff, while managing to bring back a bit of his long-time hitch in a more subdued, low-starting motion.

From his first start this year:

Quiet, low hands, consistency of motion and direction toward the plate, and, at least thus far, better command which he can hopefully carry through. The impact on Kikuchi’s release point alone is cause for encouragement that not only are his pitches slated for more success, they are coming out more consistently and better situated for command.

Release point is displayed as if viewed from home plate
Baseball Savant

Will this be enough to entreat Seattle to pick up Kikuchi’s option? Before 2021, it seemed unlikely. Now, Kikuchi is sitting 95 once more with his heat, is working in the zone but missing bats, and putting himself in position to go longer each outing. If this is a year of putting together two years worth of lessons at last, as it seems to be early on, Seattle may at last have something consistently solid in their veteran lefty.