Yusei Kikuchi Is Protecting the Ball within the Yard for a Change

The Toronto Blue Jays have devoted big assets to their rotation, spending a first-round decide on Alek Manoah, doling out big free agent contracts to Chris Bassitt and Kevin Gausman, and buying and selling the farm for José Berríos. (After which giving Berríos an enormous contract extension as effectively.)

However Toronto’s greatest beginning pitcher over the previous month — and in a three-way tie for the most effective pitcher in all of baseball, by WAR — has been Yusei Kikuchi, the man who couldn’t keep within the rotation a 12 months in the past.

Kikuchi was hardly a cut price bin pickup himself; Toronto spent $36 million over three years to signal the Japanese lefty away from Seattle. However his first season north of the border couldn’t have gone worse. Kikuchi posted a career-high ERA- of 134, and his underlying numbers confirmed that he deserved each little bit of it. Kikuchi struck out 27.3% of batters, a profession excessive, however he walked 12.8% and allowed a HR/9 price of two.06. It’s like he was making an attempt to piss FIP off.

Among the many 140 pitchers who threw at the very least 100 innings final 12 months, that stroll price was not solely the very best, nevertheless it beat the second-worst stroll price by 1.3 proportion factors. Kikuchi’s HR/9 ratio was the second-worst. Contemplating that he was swimming within the two issues a pitcher most desires to keep away from, it’s shocking that Kikuchi’s outcomes and peripherals weren’t much more abysmal.

The dangerous occasions continued till the tip of Could this 12 months, however since Memorial Day or so, Kikuchi has stopped strolling individuals and has saved the ball within the yard:

Bully for him. Drawback solved, let’s all go dwelling.

Or, we might strive to determine how he’s doing it. Chopping the stroll price is an enormous factor, clearly, and Kikuchi is throwing extra first-pitch strikes and dealing within the zone greater than he did in 2022. Aside from the stroll price, essentially the most notable change in Kikuchi’s fortunes has been a decreased high quality of contact on balls within the air. Right here’s a month-by-month breakdown of the fly balls Kikuchi has allowed as a Blue Jay, with the proportion of fly balls that left the bat at 95 mph or quicker, or had been projected to journey 330 toes or extra:

Kikuchi’s opponent wOBA on fly balls final 12 months was not solely the worst in baseball out of 415 pitchers who allowed at the very least 30 batted balls of that sort, it was the worst by 55 factors. Time was, virtually each fly ball Kikuchi allowed regarded like one thing piloted by Chuck Yeager. Now solely a few of them look that manner. Consequently, the second-most homer-prone pitcher of 2022 is now un-dingered-upon in his previous 5 begins, the second-longest streak of his profession. He’s nonetheless permitting extra harm than common on fly balls this season, nevertheless it’s livable now:

How is he doing this? Nicely, Kikuchi has modified his arm angle barely to increase his arm farther to left. Right here’s a scatter plot of Kikuchi’s common launch level by month since he joined the Blue Jays, with the months of 2023 in purple:

And that change is much more pronounced than the graph makes it look, as a result of in 2023, Kikuchi has launched a brand new pitch, a curveball, that’s he’s throwing virtually 20% of the time and releases about six inches nearer to impartial than his fastball.

If there’s a narrative to Kikuchi’s 2023 resurgence, it’s his revamped breaking ball repertoire. Final month, Nick Ashbourne tied Kikuchi’s corner-turning efficiency to the curveball’s evolution from a show-me pitch to a real weapon. And this spring, Sportsnet’s Arden Zwelling detailed the method behind Kikuchi’s new slider, which is coming in two ticks tougher this 12 months than final.

In 2022, Kikuchi was a two-pitch man in opposition to lefties, and did fairly effectively. Sadly, as a consequence of generations of social engineering which can be past the management of 1 baseball participant, most individuals within the U.S. are right-handed. Particularly, most baseball gamers. And in opposition to righties, Kikuchi received wrecked, to the tune of a mid-.400s opponent wOBA on his two mostly used pitches:

Including the curveball has given batters a brand new velocity band to look out for; final 12 months, Kikuchi was throwing his fastball at a median velocity of 94.9 mph, his slider at 86.4 and his changeup at 87.0. This 12 months, the fastball is averaging 95.3 mph, the slider 88.9, and the changeup 88.7, whereas the curveball is available in at a relatively Entlike 82.9.

I’m satisfied this new pitch is working for him, however I’m much less satisfied it’s really a brand new pitch. That is Kikuchi’s fifth 12 months within the main leagues, and solely as soon as has he saved his repertoire the identical from one season to the subsequent. This isn’t the primary time Kikuchi has used a curveball and a slider on the identical time; he did that in 2019 earlier than he launched a cutter and junked the deuce.

However that wasn’t the identical curveball he’s throwing now. In truth, Kikuchi’s present curveball resembles his 2020-21 slider greater than his 2019 hook:

Kikuchi has thrown 344 curveballs this season. I went again and located the median 50% for that pitch in velocity and motion. Meaning a velocity of between 82 and 85 mph, with between 39 and 47 inches of drop and between 4 and eight inches of glove-side break.

Kikuchi has thrown 153 breaking pitches that meet these standards in his profession: 70 curveballs, all thrown this season, and 83 sliders, all thrown between 2019 and 2022. What I stated a pair paragraphs again in regards to the new curveball and the outdated slider being the identical pitch was just a little glib; the pitches marked as curveballs spin, on common, about 140 rpm quicker than the sliders, although there may be some overlap. Furthermore, this 12 months’s curveball has extra common horizontal break than any slider Kikuchi has ever thrown. These are in all probability two distinct pitches with related motion profiles.

However I’m unsure saying that Kikuchi “added a curveball” is the correct manner to have a look at this. That is the second season through which Kikuchi has averaged about 95 mph on his fastball, offset by a breaking ball with a median velocity of about 83 mph. The opposite 12 months that match these standards was 2021, when he was an All-Star.

What modified between 2021 and 2022? Kikuchi (for all intents and functions) stopped throwing his cutter. And as a lot as I’d like to go on one other rant about how pitch classification is an inexact science and Kikuchi’s outdated cutter is now a slider and his outdated slider is now a curveball, that’s not the case. The cutter, might it relaxation in peace, was a low-90s pitch with a lot much less break than Kikuchi’s present upper-80s slider. But it surely looks as if Kikuchi’s low-80s breaking ball, no matter it’s or no matter it’s known as, wants a tougher, tighter sibling as a way to be efficient. Kikuchi didn’t have that final 12 months, and he received crushed. Now that he’s received it again, he’s on the most effective run of his profession.