Last Updated on September 4, 2020 by Luke Arkins

A difficult 2019 rookie season morphed Yusei Kikuchi into the most enigmatic player on the Seattle Mariners. Still, Kikuchi may be turning a corner this year. We’ll get to the improvements he’s been demonstrating in a moment. First, let’s quickly revisit his pitching record from last season.

As Mariners fans know all too well, Kikuchi was frustratingly inconsistent and mostly ineffective last year and the stats prove it – he ranked near the bottom in most categories. The following table helps put those struggles into perspective. Illustrated are the left-hander’s numbers, the MLB average for each statistic, plus his ranking among 108 pitchers facing 500-plus hitters in 2019. Statistically speaking, the baby was ugly.

Yusei Kikuchi’s 2019 Numbers

Kikuchi
MLB
Rank**
ERA
5.46
4.54
98
AVG
.295
.256
102
OBP
.348
.320
95
SLG
.539
.444
106
SO%
16.1
22.3
101
BB%
6.9
7.7
47
HR/9
2.0
1.4
105
WHIP
1.52
1.32
101
xwOBA
.341
.318
96
** Rank among 108 SPs with facing 500+ hitters

Despite underwhelming season numbers, Kikuchi occasionally managed to shine – 12 quality starts, including a complete-game shutout. Moreover, his 162.1 innings pitched ranked second on the Mariners behind Marco Gonzales (203). In retrospect, those sporadic flashes of brilliance had to be what GM Jerry Dipoto was expecting on a regular basis. Otherwise, why sign the Japanese hurler to a four-year/$56 million deal, which could potentially become a seven-year/$109 million commitment?

Improving Numbers

So, what suggests Kikuchi may be turning a corner this year? Let’s start with his conventional line. As we’ll see below, the 29-year-old is demonstrating significant improvement in many categories with the exception of ERA and walks.

Conventional Stats Looking Good

2019
2020
MLB
ERA
5.46
5.28
4.13
AVG
.295
.250
.251
OBP
.348
.323
.322
SLG
.539
.304
.432
SO%
16.1
25.8
23.0
BB%
6.9
9.7
8.6
HR/9
2.0
ZERO
1.27
WHIP
1.52
1.304
1.26

Despite the higher rate of walks allowed, Kikuchi is allowing fewer base runners. Moreover, he’s yet to surrender a home run. In 2019, susceptibility to the long ball was a significant issue for the eight-year veteran of Japan’s Nippon Professional Baseball.

Kikuchi is also striking out more hitters than last year. It’s worth noting his 25.8-percent strikeout rate at this early stage of the season is nearly identical to the combined strikeout rate posted during his final three seasons in Japan (25.5).

Advanced metrics paint an even rosier picture of Kikuchi’s 2020 and help relieve the sting of his high ERA. First, he’s avoiding well-struck balls more often. His hard hit rate is down by 5.1-percent and he hasn’t given up a “barreled” ball in 2020. The Statcast range for barrels begins with an exit velocity of at least 98-MPH and a launch angle between 26-30 degrees. Last season, barreled balls produced a .816 and 1.446 wOBA in MLB.

Advanced Metrics Favor Yusei Even More

2019
2020
MLB
Hard Hit%
39.1
34.0
34.7
Barrel%
7.7
ZERO
6.3
GB%
44.8
57.5
45.3
FB%
21.9
12.5
22.0
LD%
25.1
27.5
25.5
wOBA
.368
.280
.317
xwOBA
.357
.270
.330

The decline in hard hit balls is a welcome sign. So is Kikuchi avoiding airborne damage thus far. His 57.5-percent ground ball rate is thirteenth highest in the majors among starting pitchers. What’s prompting the hefty jump in grounders this season? Apparently, a pitch Kikuchi didn’t use last year.

Kikuchi 2.0

Per Statcast, Kikuchi is throwing a cutter, which wasn’t in his 2019 repertoire. Essentially, it’s supplanted the curveball, which hasn’t appeared this year. Here’s a breakdown of his pitch usage rate, plus wOBA and ground ball rate for each pitch.

Kikuchi’s Pitch Utilization (2019 v 2020)

Year
Pitch Type
Usage %
wOBA
GB%
2020
Cutter
42.5
.218
35.0
2020
Four Seamer
40.2
.380
10.0
2020
Slider
11.8
.348
10.0
2020
Changeup
5.5
.174
2.5
2019
Four Seamer
49.0
.410
18.2
2019
Slider
28.0
.342
14.8
2019
Curve
15.4
.409
5.5
2019
Changeup
7.6
.239
5.3

Not only has Kikuchi relied on a cutter more heavily than any other pitch, it’s producing a superb .218 wOBA. It’s also generating a 35-percent ground ball rate. That’s nearly two-thirds of all grounders produced by the sophomore in 2020.

A new pitch wasn’t the only upgrade Kikuchi made. It’s been widely reported he partnered with Driveline Baseball in the offseason to improve his mechanics and ultimately the overall effectiveness of his arsenal. Evidence of change was initially on display during Spring Training – a streamlined delivery with increased fastball velocity. What we’re also seeing now is a more aggressive Kikuchi, who’s making opposing hitters swing and miss more often.

Kikuchi’s 30.5-percent swing and miss rate (Whiff%) is top-30 in the majors this year. Conversely, his 20-percent rate was in the bottom-30 in 2019. For anyone wondering, Whiff% is the percentage of swings resulting in strikes. The following illustrates the Whiff% for each of Kikuchi’s pitches in 2019 and this year.

Yusei’s Climbing Whiff Rates

2019
2020
Four Seamer
16.0
29.4
Cutter
N/A
30
Slider
25.9
36.4
Changeup
23.5
33.3
Curve
15.4
N/A
Overall
20.0
30.5

Assuming the new and improved Kikuchi is here to stay, it’s plausible he could become the most valuable pitcher on the staff this season. Some may consider suggesting he surpasses Gonzales as the Mariners’ top starter as blasphemy or just utter nonsense from a knucklehead like me. But why not?

If hitters continue driving the ball into the dirt against Kikuchi and the southpaw can dominate with swing and miss stuff, why couldn’t he become Seattle’s top gun? It’s a realistic possibility – at least to me it is.

Reality Check

Now, I know what some of you are thinking. It’s early and Kikuchi’s small body of work amounts to a teeny sample size – three starts and 15.1 innings to be exact. Yes, it would be premature to claim a star is born. A healthy amount of skepticism is understandable, especially after his disappointing rookie debut last year.

Still, what if Kikuchi has figured something out?

If so, he could be a fixture in the Mariners’ rotation when the team turns its corner. It certainly would be helpful to have a dominant Kikuchi and a reliable Gonzales leading the organization’s stable of young guns – Justus Sheffield, Justin Dunn, Logan Gilbert, George Kirby, Emerson Hancock, Brandon Williamson, and Isaiah Campbell.

Perhaps the Marco/Yusei tandem happens. All that’s needed is for Kikuchi to sustain his recent excellence.

I believe he can do it.

My Oh My…

Image courtesy of Stephen Brashear | AP Images
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