It’s my least favorite sentiment to engender, and one of the worst to feel yourself. Disappointment is the bogeyman that cannot be outrun, fleeing just temporarily when a light is shone upon it. There is safety in failing at something you are unequipped to undertake - a plausible deniability that reassures you “of course it’s not your fault, you were never going to succeed anyway.” Parker Markel or Ruben Alaniz are not disappointments when they struggle, even if it may be disappointing they are in a particular situation. They are longshots making the absolute most of their abilities, with little expectation ascribed. Yusei Kikuchi had more potential than any pitcher on the Mariners 2019, and likely their 2020 Opening Day roster as well. Last year, his season was a thorough disappointment.
There was not much to look forward to for the 2019 Mariners, but Kikuchi was supposed to be part of it. Armed with a ballyhooed plan for transitioning Kikuchi into MLB, the lefty instead struggled with command and consistency in his stateside debut. His season was beset with off-field stressors - the death of his father and the birth of his first child - and just as we might expect a change in performance from an office worker or a student suddenly facing massive upheaval in their life, Kikuchi is due some leeway. A bad season on the field does not dissipate the promise his past suggests. All the same, it’s worrying to see Seattle’s lone free agent ~splurge, who was seemingly wooed at least in part by a well-developed plan for his assimilation, struggle as mightily as he did.
The best of Kikuchi flickered in and out. He’d unsurprisingly show dominant stuff in shorter outings, but struggle to maintain command through 5-7 innings. After a difficult April, the first short start of the season seemed to invigorate the lefty. He wove together four straight quality starts against Cleveland, the Yankees, the Athletics, and the Twins - all quality offenses. And yet consistency eluded him. His velocity fluctuated between outings, as did, somewhat worryingly, his spin rates, which can often be a warning sign for injury. His go-to slider, expected by scouts to translate well to the bigs, failed to get hitters to bite, as Kikuchi failed to get swings out of the zone despite having no issue doing so in the NPB.
By late in the season, the organization was having some success working with Kikuchi on mechanical adjustments, shortening his hitch-heavy motion into a more fluid process. The slicker, larger MLB ball clearly impacted Kikuchi’s ability to utilize his breaking balls, but it was still shocking to see him struggle as consistently as he did across the board. Of 105 pitchers in 2019 who threw at least 2,000 pitches, no pitcher in baseball gave up more damage over the plate than Kikuchi, with a .402 wOBA allowed on pitches in the zone. If hitters got the bat on a pitch in the zone from Kikuchi, they hit like George Springer. Combine that with a sub-30% O-Swing rate and a single-digit 8.8% whiff rate, and you get Kikuchi’s 2019: grisly results with no salvation coming from the peripherals. If there is hope to be had, only one pitcher in baseball - Minnesota’s Martin Perez - had a greater discrepancy between their xwOBA and their actual wOBA allowed, which suggests Kikuchi may have been somewhat unlucky, or at least suffered from the 2019 Mariners’ historically awful defense. Beyond that, Seattle’s analytics team may be better equipped to set up behind Kikuchi with a year more of data.
Digging that deep to find something to cling to, unfortunately, doesn’t bode well. Most promising, perhaps, is that Kikuchi is no stranger to making adjustments. If his original signing information is to be believed, the fact that the Mariners could provide a low-stakes environment in the first year or two for Kikuchi to adjust was part of the long-term appeal for him. We’ve seen one year of it all going awry, and all we have to go on for the future is success from his international past. The stuff remains more impressive than any Mariners starter short of perhaps Justus Sheffield, but like his young rotation-mate, 2020 may suddenly be make or break in the rotation. The stakes for the team remain low, but the potential Kikuchi still has gives him a chance to erase his disappointing debut. Make this winter count, because 2020 matters, at least for Kikuchi’s own future.