Blue Jays Rogers Centre- Credit: DaveMe Images

Kikuchi: A Blue Jays Rotation Candidate

The Toronto Blue Jays are reportedly in the market for another starting pitcher. One of the names bandied about by baseball observers is Yusei Kikuchi. Is he a good fit for the Blue Jays?

Featured Images Courtesy Of DaveMe Images. Prints Available For Purchase





Before MLB locked out the players, the Blue Jays added Kevin Gausman to the rotation. However, 2021 Blue Jays starters Robbie Ray and Steven Matz departed for other pastures. Baseball onlookers have floated the name of Yusei Kikuchi as a potential free-agent target.


Kikuchi was born on June 17, 1991, in Morioka, Japan. After a nine-season career with the Saitama Seibu Lions of the Nippon Professional Baseball League, he joined the Seattle Mariners before the 2019 season. With the Mariners, Kikuchi posted a 4.97 ERA, 4.93 FIP and a 4.43 xFIP. After the 2021 campaign, the Mariners decided not to exercise their option to secure Kikuchi’s playing rights with a 4-year, USD 66 million contract. Subsequently, Kikuchi did not exercise his one-year, USD 13 million player option. Kikuchi is now a free agent.


On the surface, Kikuchi’s ERA and other metrics do not scream “sign this player.” However, he posted a 3.40 xERA and 3.30 FIP in the pandemic shortened 2020 campaign. Kikuchi continued to pitch well during the pre-July 1 period of the 2021 season: he recorded a 3.34 ERA and appeared in the 2021 All-Star game. However, his post-June 30, 2021 season was poor (5.73 ERA and a 4.94 FIP). Yet, Steamer projected a 4.03 ERA and a 2.2 fWAR for 2022 Kikuchi, similar to Steamer’s estimate for Matz (3.91 ERA and 2.4 fWAR).


Could Kikuchi be an able replacement for Matz? Let’s dig a little more into the Kikuchi case!

Pitch mix

Table 1 presents Kikuchi’s pitch arsenal for the 2019-2021 period. The highlights are as follows:

  • Since 2019, Kikuchi’s debut season, he eliminated the curveball and introduced the cutter
  • In 2020 and 2021, Kikuchi’s repertoire was primarily four-seamers, cutters and sliders


An interesting note is the velocity on Kikuchi’s four-seam fastball. In his rookie season, Kikuchi’s average velocity on the four-seamer was 92.5 mph. However, in 2020 and 2021, the average velocity was 95.0 and 95.1, respectively. That pitch velocity would not surprise scouts who witnessed Kikuchi reach 96.0 mph as a high-school pitcher.

Starter performance levels

Suppose that a #1 starter’s ERA lies within the 81st to 100th percentile of starter ERAs. A #2 starter’s ERA resides in the 61st to 80th percentile, and so on. Also, one can separate other critical metrics into percentile bands for starters. For an explanation regarding percentiles and starter percentile breaks, please refer to the Appendix.


Matz’s 2021 production placed him in a weak #2/strong #3 slot in the rotation. Last season, Matz’s fWAR was 2.8, which was 75th percentile. His ERA, FIP, and xERA percentile rankings were 63rd, 71st and 62nd.


Concerning Steamer’s 2022 estimates, Kikuchi’s ERA, FIP and fWAR rank in the 71st, 67th and 63rd percentiles, respectively. Based on Steamer’s figures, Kikuchi would be a weak #2/strong #3 starter. Matz who? Hello Kikuchi? Not so fast; there are some red flags to consider.

The numbers

Table 2 shows some critical metrics for Kikuchi.


Kikuchi has not excelled in the ERA department. His best ERA season was 2021, when he registered a 4.41 ERA (44th percentile), higher than the 4.25 median of 2021 MLB starters (minimum 50 innings pitched). Seattle’s poor defence likely contributed to Kikuchi’s elevated ERA throughout his MLB career. The Mariner’s OAA has been below-average in all three of his MLB campaigns: 2019 – (-25); 2020 – (-1); 2021 – (minus 7).


From the perspective of replacing Matz, FIP is the best argument for Kikuchi. His 2020 FIP of 3.30 was 83rd percentile. However, there are many possibilities concerning why Kikuchi’s FIP was much better in 2020 than 2019. Below are four to consider.

  • First, small sample sizes were in play in 2020. The 2020 regular-season schedule was 60 games, considerably less than the standard 162-game calendar. Kikuchi had only nine starts in 2020.
  • The following three factors can be summed up as opponents either not seeing Kikuchi often or seeing a different Kikuchi in 2020.
  • In 2019, Kikuchi faced ten teams at least twice; only two ball clubs saw him for the second time in 2020. Of the two occasions when Kikuchi faced an opponent for the second time in 2020, he had one below-average Game Score. When facing a team the second time in 2019, Kikuchi’s Game Score was below-average eight times.
  • Kikuchi’s pitch mix changed considerably in 2020. He eliminated the curveball, added the cutter and reduced the slider usage by almost 50%.
  • As I noted earlier, the velocity on Kikuchi’s four-seam fastball increased by 2.5 mph in 2020 compared to 2019.


In my opinion, Kikuchi’s 2020 FIP appears to be an outlier due to the shortened schedule, including Kikuchi’s lack of exposure to rival ball clubs for a second time and pitch mix and velocity changes not previously seen by opposing teams.


Table 2 also illustrates that Kikuchi’s expected stats do not support Kikuchi’s candidacy as a suitable replacement for Matz. His 2021 and 2019 Hard Hit%, xERA and xSLG percentile rankings support the opinion that Kikuchi will perform at the level of a weak #4 rather than 2021 Matz’s weak #2/strong #3 slot.

Kikuchi: User of sticky substances?


Partway through the 2021 season, MLB implemented a crackdown on pitcher use of banned sticky substances. The official enforcement date was June 21.


The pitchers who employed sticky substances did so because it increased the pitched ball’s spin rate, enhancing ball movement and making the pitch more challenging to hit. In the case of a four-seam fastball, applying stuff to the baseball allows the pitch to hold its line longer, giving the impression to the batter that the pitch is rising. For the slider, more spin means more horizontal movement.


Below is an excerpt from an article I wrote in June 2021.

In 2016, Driveline Baseball concluded that it “was nearly impossible to increase rpm/mph ratios for fastballs without more velocity or sticky stuff. They determined pitchers have natural rpm/mph fastball signatures that are constant with velocity change.”

According to University of Illinois physics professor Alan Nathan, an MLB consultant, “it’s probably pretty hard to change that [fastball spin] ratio for an individual.” Nathan did say that a pitcher could naturally change a curveball’s spin rate. However, to do so requires finesse; a fastball needs much less finesse.”


Kikuchi: The sticky data

Table 3 shows Kikuchi’s Bauer Units (Spin Rate divided by Pitch Velocity) before July 1 and after June 30. A Bauer Unit reduction amounting to one or more is consistent with a pitcher ending their usage of a banned sticky substance.


Compared to 2020 and 2019, the Bauer Units of Kikuchi’s four-seam fastball and cutter increased considerably during the April-June segment of the 2021 season. The slider’s 2020 Bauer Units was noticeably less than in April-June, 2021.


For those interested, Kikuchi’s spin rate on his 2020 slider was similar to that employed during the second half of the 2021 season. In 2020, Kikuchi increased the spin rate and lowered the average velocity of his slider, which accounts for the Bauer Unit increase from 2019 to 2020.


Most importantly, Kikuchi’s OPS and xOPS against rose appreciably during the post-June 30 period in 2021. These OPS and xOPS marks were higher than the American League average, which was not the case during the April-June period.


As a comparison point, there is the case of Gerrit Cole. Many baseball observers linked Cole’s name with sticky substances. When reporters asked Cole in June 2021 about sticky materials, Cole danced around the topic. After MLB’s crackdown commenced, there was a noticeable decline in the Bauer Units of Cole’s four-seam fastball and slider. However, Cole’s xOPS against was essentially unchanged. Before the crackdown, his xOPS against was 0.598; it was 0.656 after. Both of these figures were below MLB’s average 0.729 xOPS. Excellent pitchers can benefit from sticky substances, but outstanding pitchers can be superior without the stuff.


It cannot be stressed enough that a Bauer Unit reduction may or may not be due to the pitcher ceasing to use a sticky substance. Such a reduction is consistent with the absence of a sticky material but not necessarily determinative.


With that proviso, Kikuchi’s post-June 30 poor performance is consistent with a pitcher who struggled after ending usage of banned sticky substances.

Kikuchi – Is he a #3, #4 or #5?

The answer to this question depends primarily upon how much weight one wishes to place on small sample sizes and which sample.

  • Is it the 2021 sticky-stuff-free part of the season?
  • What about the April-June period of 2021?
  • Is it the pandemic-shortened 2020 campaign?


For the reasons previously discussed, I put less weight on Kikuchi’s 2020 and the first half of the 2021 campaign. I emphasize the July-October part of the 2021 season of the noted short periods. Moreover, the entirety of Kikuchi’s career indicates that he is a #4 starter. During the 2019-2021 seasons, the percentile rankings of his 4.97 ERA and 4.93 FIP are 23rdand 26th, respectively.


Furthermore, Sam Sharpe wrote an interesting article regarding Expected Weighted On-Base Average. The piece included his finding that the ERA-predictive value of a pitcher’s Barrel%+BB%-K% metric is higher than FIP and xFIP.


In 2021, Kikuchi’s Barrel%+BB%-K% metric was 34th percentile among pitchers who faced a minimum of 300 batters (192 pitchers). This ranking is consistent with the view that Kikuchi’s 2022 ERA will be #4- starter level.

Contract estimate

In my view, Steamer’s 2.2 fWAR projection for Kikuchi is high. Suppose a fair estimate of Kikuchi’s 2022 ERA lies somewhere between the 30th and 40th percentile of Steamer’s 2022 projections. Accordingly, the average fWAR of the 22 pitchers with an ERA within the 30th and 30th percentile bands is 1.5.


When I apply the 1.5 fWAR to the calculation found in Table 4, Kikuchi’s two-year, USD 19.7 million contract aligns with the MLBTR estimate. My guesstimate on a one-year deal for Kikuchi is USD 10.8 million, which is in the ballpark of FanGraphs USD 8.0 million figure.

Arguments for and against signing Kikuchi


  • If Kikuchi is willing to sign a one-year, USD 8 million contract, his deal would be fair value for a #4 free-agent starter.


  • The previously maligned Steamer projects that the 2022 version of Nate Pearson will produce a 1.4 fWAR in 129 innings. That production is similar to my estimate of Kikuchi’s 2022 performance. The Blue Jays can use the dollars saved otherwise used to sign Kikuchi to address other roster needs.
  • Considering that Kikuchi appears to be firm regarding a multi-year contract, a financial commitment beyond one season seems excessive for a #4 starter when other options are available.


I would not sign Kikuchi to a two-year, USD 20 million contract considering all factors. His body of work indicates that he is a #4 starter with limited upside. If I were the Blue Jays, I would exhaust other starting pitching options before agreeing to such a contract for Kikuchi.

The last word

Many media outlets have reported that the Toronto Blue Jays are interested in adding another starter to the rotation. A potential candidate for a role in the Toronto rotation is Kikuchi. However, in my opinion, he is, at best, a #4 starter. Furthermore, many outlets have reported that Kikuchi is seeking a multi-year contract, which is excessive given his expected performance level. I believe the Blue Jays should consider other options before committing to Kikuchi.




*Featured Image Courtesy Of DaveMe Images. Prints Available For Purchase.





Bob Ritchie

Bob was a St. Louis Cardinals fan until the Blue Jays arrived on the baseball scene, although he still has a soft spot for the Cards. Similar to straddling the Greenwich Meridian, as depicted in the avatar, Bob applies sabermetrics when applicable, but his heart tells him that Lou Brock belongs in the Hall of Fame.