2021 Seattle Mariners: New And Improved Yusei Kikuchi

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In the two seasons as a Seattle Mariner, Yusei Kikuchi has had mixed results. The 2021 Seattle Mariners will look for a step forward from the originally highly touted arm after coming over from the KBO.

In his two previous seasons, Kikuchi has been somewhat disappointed considering the lofty price tag that came with signing him. Kikuchi has thrown 208.2 innings in two seasons and carries a less than ideal ERA of 5.39 with underlying stats that don’t help his case as someone who might turn it around anytime soon.

2021 Seattle Mariners: Help Coming From The Inside

In his rookie season in MLB, Kikuchi would pitch 161.2 innings over 32 games, with all of them being starts. The end season numbers pretty ugly, with an ERA of 5.46 while also having his FIP and xFIP over 5.00; it’s safe to say 2019 wasn’t the year anyone was expecting out of the promising left-hander.

Over his 32 starts in 2019, Yusei Kikuchi didn’t show enough swing and miss many among the industry to question how effective he would become. His Whiff rate landed him in only the 10th percentile in MLB and led to a disappointing 16.1% strikeout rate. Although Kikuchi did post an impressive 6.9% walk rate, that wasn’t enough to knock off the opposing batter when they made contact.

Opposing batters crushed the ball off Kikuchi, with an average exit velocity and hard-hit rate in the 27th and 33rd percentile among qualified MLB pitchers. The mix of hard contact and lack of strikeouts lead to an extremely disappointing .352 xwOBA and a .368 wOBA.

Fast forward to the end of the 2020 season, and Yusei Kikuchi would have a disappointing season looking at his ERA’s surface that again was north of 5.00 (5.17). When you take a deeper look into his numbers, we could be witnessing Kikuchi transforming into the impactful MLB rotation arm many were hoping for two seasons ago.

2019 (161.2 Innings pitched)5.715.185.17
2020 (47 Innings pitched)5.173.304.34

2021 Seattle Mariners: What Changed In 2020?

Yusei Kikuchi, when he originally came over to MLB, Kikuchi wasn’t known as a massive strikeout pitcher, coming over with a career 8.0 strikeouts per nine innings in his nine years in Japan.

Kikuchi in 2020 took a solid step forward in the swing and miss department. Improving upon his sub 20% strikeout rate, making the improvement that rose that number up to 24.2% at the cost of his 6.9% walk rate up to 10.3% in 2020. The improvement in strikeouts is sustainable if Kikuchi keeps his whiff % (pitches swung at and missed) that he increased 10% from 20% up to now 30%.

When many pitchers are looking for increased velocity, The 2021 Seattle Mariners hope Kikuchi can keep the increased velocity on his 92.4 MPH fastball; in 2020, it sat on average 95 MPH. Kikuchi also added a cutter to his repertoire, and it appears to be paying off big time.

A change from 2020 that the 2021 Seattle Mariners should stick with is the repertoire tweak. The addition of a brand new cutter meant fewer fastballs that he threw 49% of the time in 2020, and opposing hitters would have a slugging percentage of .622; that number with decreased fastball usage would drop to a .288 slugging percentage on the pitch. With the cutter addition, Kikuchi would eliminate his curveball, a pitch that gave up a .431 xwOBA to opposing batters.

With the improvements made in 2020, the 2021 Seattle Mariners will look for the improved batted ball numbers off Kikuchi to stick. In 2020 Kikuchi increased his ground-ball rate by 8% up to 52%. Kikuchi’s barrel rate in 2020 was in the 86th percentile, in large part due to his improved ability to draw groundballs.

In 2019 Yusei Kikuchi gave up 36 home runs to opposing batters. In 2020 Kikuchi would only give up three home runs over the shortened season. If we average it out, Kikuchi would’ve been on pace to give up nearly less than 20 from the year prior.

The 2021 Seattle Mariners will look for Kikuchi to be the team’s number two starter behind Marco Gonzales. If all goes well and Kikuchi continues to improve upon his game, we could see an effective rotation for the 2021 Seattle Mariners with an improved Kikuchi.

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Main image credit: Embed from Getty Images

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Murray is a college student attending Humber College for Sport Business, can be found on Twitter at @_MurrayBrown