Is Shota Imanaga the Most Intriguing Pitcher of the Offseason?

Photo by Daniel Shirey/WBCI/MLB Photos via Getty Images

The 2023-24 MLB offseason newscycle has been dominated by the free agencies of Shohei Ohtani and Yoshinobu Yamamoto; however, now that both superstars have agreed to terms with the LA Dodgers, attention shifts to several others on the market, such as two-time Cy Young winner Blake Snell, 2023 World Series champion Jordan Montgomery, 2019 NL MVP winner Cody Bellinger, and two-time platinum glove winner Matt Chapman. Yet, perhaps the most thought-provoking free agent left on the market is another Japanese star, Shota Imanaga, who was posted by the Yokohama DeNA Baystars this winter and has drawn interest from several Major League teams, such as the Boston Red Sox, San Francisco Giants, New York Yankees, New York Mets, Chicago Cubs, and Los Angeles Dodgers.

Shota Imanaga is coming off of the best two-year stretch of his eight-year career for the Baystars, posting some great seasons over this span.

Data courtesy of Deltagraphs

While it is important to simply look at these numbers, it is even more essential to note that the offensive environment of NPB in 2023 is among the worst in recent memory; thus, why I included Imanaga’s FIP-. Like all statistics ending with a + or -, FIP- is park and era adjusted, making it easier to compare data across different eras and run-scoring environments. No matter what, league average is set at 100, and, in the case of FIP-, every point below 100 indicates a park and era adjusted FIP better than the league average. This is important to note as I compare Imanaga to fellow NPB pitchers who were posted and signed with a Major League team.

Data courtesy of Deltagraphs

While Imanaga is not the overall package that Senga, Maeda, Ohtani, and Yamamoto are/were advertised as, from a pure stuff perspective, he may be on par or even better than them. From a K% standpoint, only Ohtani ranked higher than Imanaga. However, no one among these four, and of all NPB pitchers in 2023, struck out as many batters while limiting the free passes to the level of Imanga at 25.2%. Imanaga throws his fastball, his most frequently used pitch, for strikes 74% of the time, well above both MLB and NPB averages for the pitch, enabling him to limit the amount of walks given up. However, despite this high strike rate, his command has been shaky at times, opening him up to damage. On the fastball in 2023, Imanaga’s Location+, a count and pitch type-adjusted judge of a pitcher’s ability to effectively locate pitches, was 112—indicating that he has above-average command of the pitch overall.

While I have highlighted his ability to strike out many while limiting walks, it is essential to note his incredibly high fly ball and home run rates. Imanaga has posted fly-ball rates of 53.3% in 2022 and 55.8% in 2023, which were the highest marks among qualified pitchers in NPB in both years. The susceptibility to the fly ball leads Imanaga to thus be prone to high home run rates. Over the past two years, amidst the NPB dead ball era, Imanaga posted HR/9 of 0.88 in 2022 and 1.03 in 2023, which ranked sixth and first, respectively, among all NPB qualifiers. In fact, Imanaga’s HR/9 of 1.03 in 2023 has only been matched thirty times total among qualified NPB pitchers in the last decade (2014 is the furthest back Deltagraphs’ measurements of this statistic goes)–the majority of which coming from 2017 through 2021, times, even just two years ago, where the offensive environment was much healthier for run scoring.

Imanaga’s fly ball and home run rates are drastically higher than that of both his leaguemates and fellow NPB postees who have come/are coming to Major League Baseball. While this is a cause for concern as he comes stateside, the high fly ball rates are something that teams will have to either learn to live with or adjust his approach in order to mitigate the damage.

Pitch Mix

To this point, we have examined Imanaga’s impeccable K/BB, perhaps his greatest strength, and his extreme fly ball rates, maybe the most significant concern in Imanaga’s game. We will shift courses to look towards what makes up the pitcher that is Shota Imanaga by examining his pitch repertoire.

Imanaga, akin to the recently signed Yamamoto, does not have an overly imposing presence on the mound, standing at 5-10 and weighing 176 lbs. The lefty features a 4-seam fastball, sweeper (which in his case is his slider), splitter, cutter, curve, and sinker. While he features six different pitch types, he relies almost exclusively on the fastball, slider, and splitter combo, which comprised over 80 percent of his total pitches thrown in NPB.

Fastball

Imanaga features a four-seamer, which he utilizes 51.2% of the time, according to DeltaGraphs. As aforementioned, he threw this pitch for a strike 74% of the time in 2023 with a swinging strike rate of 12%. According to DeltaGraphs calculations of NPB pitch values, Imanaga’s four seamer had a wFA (Fastball runs above average) of 8.5, making it the seventh most valuable four seamer in all of NPB in 2023. In fact, in 2022, with a wFA of 21.1, Imanaga’s fastball was the most valuable in all of NPB that year.

It averages out at 91.8 MPH, sometimes working up to 94 MPH on occasion, a jump from early in his career, where, in his rookie year with the Baystars in 2016, he averaged out at 87.2 MPH on the pitch. While this pitch sits a couple ticks below the Major League average, one aspect of the pitch that intrigues scouts is the fact that it has over 20 inches of induced vertical break, a number that is incredibly rare for a lefty, especially considering his release point for the pitch being only 5.5 feet above the ground. Regarding pitch shape, the closest comparisons that can be found to Imanaga’s four-seamer are that of Nestor Cortes and Alex Vesia–in terms of velocity, iVB, and release height. While Cortes and Vesia induce similar ranges of iVB, both have release points closer to the Major League average on the pitch.

According to data from SPAIA, Imanaga surrendered 14 homers on the pitch. However, these home runs can become more palatable when batters hit .224 against the pitch, and Imanaga scarcely hands walks out. In MLB, teams may have to be willing to deal with the high home run rate, especially in the current offensive environment, under the notion that the majority of said homers will be solo shots.

Imanaga Heat Maps courtesy of SPAIA

Imanaga’s high strike rate and in-zone rate on the four-seamer make him incredibly vulnerable to the long ball; yet another aspect that has not been discussed yet is the sheer amount that he throws low in the zone. The heat maps above indicate where Imanaga likes to work against both left-handed and right-handed batters, and they show, simply, that he works low in the zone. Much of this can be partly due to Japanese pitching philosophy, as pitchers consistently learn to keep the ball down from a young age. If Imanaga is going to succeed in MLB, he will have to be willing to work up in the zone far more often with his fastball, which is something that whichever team signs Imanaga will most certainly address and work on in his transition to America.

Slider/Sweeper

Imanaga’s slider is his most heavily used secondary pitch against lefties, using it nearly 25% of the time versus them, compared to just 8% usage against righties and 15.6% overall. His slider is his putaway pitch against lefties and should continue to serve him well in that role when he comes to Major League Baseball. He has two variations of the pitch: a sweeper, which he uses less often and sits in the low 70s in terms of velocity, and a more traditional slider, sitting closer to 82-83 MPH. According to DeltaGraphs calculations of pitch values, Imanaga’s slider had a wSL (Slider runs above average) of 3.8, making it the seventh most valuable slider in NPB.

Splitter/Changeup

Imanaga also employs a splitter, which in his case is a very intriguing pitch, as he utilizes three different grips: two splitters and a changeup. He uses one of the three grips roughly 16% of the time; however much more frequently against righties. Imanaga gets a lot of swing and miss from his splitter, with a whiff rate above 40% (41.9 to be exact) and induces quite a bit of ground balls. While he utilizes two split-finger grips and a changeup, he induces a heavier percentage of ground balls against his two splitters rather than his change (55% on the split, roughly 44% on the change). He may look to utilize these pitches more as he comes to Major League Baseball as he and whichever team looks to sign him will look to limit his fly ball rate, as he induces a ground ball rate well above his cumulative total (34.8% in 2023) from these pitches.

Curveball

Imanaga also has a curveball, which he uses far less frequently, at only 7.8% of his total pitches thrown in 2023. Comparably to his 4-seamer, splitter, and slider/sweeper, Imanaga has incredibly shaky command on the curveball, with a Location+ of 79 and a strike rate of 50% in 2023. The pitch sits at an average of 71.9 MPH and is mainly used to catch batters off-guard and off his fastball, splitter, change, and slider. He employed the pitch at a slightly higher rate against righties—8.7% vs 7.4%---but generally is not a go-to pitch in any scenario.

Cutter

He also makes use of a cutter, but very infrequently, at a rate of just 4.1% in 2023. Usage on the pitch was down nearly 10% from 2022 when he utilized the pitch at a rate of 14.0%. The pitch averages out at 86.7 MPH, and he has decent control of the pitch, with a Location+ of 121, yet, it was his worst-performing pitch in 2023, and he began to limit its usage in 2023 due to that.

What to Expect/Projections

Now that the dust has settled on the Ohtani and Yamamoto free agent sweepstakes, teams are turning their attention to Blake Snell, Jordan Montgomery, Lucas Giolito, and Shota Imanaga. Most models project Imanaga to get a contract in the range of 4-5 years and $15-20 Million AAV. I see him getting a contract for 5 years worth $22 million AAV ($110 M in total). As large market teams, such as the Yankees, Red Sox Giants, Cubs, and Mets, missed out on Yamamoto and Ohtani, they may be more inclined to offer a secondary player on the market, such as Imanaga, slightly more AAV, getting decent production for significantly less money. Teams have fallen in love with his pitch shape data on his fastball, and one of those teams is sure to offer him a contract north of $20 million to secure his services. Fangraphs’ ZiPS projection system has Imanaga with the following numbers in 2024:

ZiPS has Imanaga in a similar range, production-wise, to Yoshinobu Yamamoto in 2024. It has Yamamoto with a 3.52 ERA, 118 ERA+, 167 K, and 3.8 WAR, albeit in 33.2 more IP. The ZiPS K/9 from Imanaga is higher than Yamamoto, but that is to be expected given Imanaga’s impeccable numbers in NPB in terms of strikeouts. On a per-inning basis, ZiPS has Yamamoto and Imanaga relatively similar production-wise. However, ZiPS has always liked Imanaga in its modeling due to his high K rate and ability to limit the walk.

In terms of Imanaga’s production stateside, I feel he should fare quite well, but perhaps not to the extent that ZiPS sees. If he stays healthy, he should eclipse the mark of 138.2 IP and the 150 IP threshold and possibly be a qualifying starting pitcher with 162 IP. I take the under, however, on his K/9, as I see the 9.8 K/9 number from ZiPS as a bit aggressive for a guy who will be making adjustments to his arsenal. Based on available data and past results from fellow NPB postees, I see Imanaga closer to 8.5 K/9 in his first season in the Majors. I also see him around a 3.6-3.7 ERA-wise, depending on where he ends up signing. While he is not the potential ace that is Yamamoto, Imanaga should be a quality mid-rotation arm for the foreseeable future due to his electric stuff. Still, everything will be contingent on his ability to limit home runs.

I believe Imanaga would benefit from a “pitcher’s park” as he comes to the States. Of those interested, San Francisco’s Oracle Park would be an incredibly beneficial home field for Imanaga as he comes to the States. As aforementioned, Imanaga concedes a hefty number of fly balls, and notably, Oracle Park holds balls in the yard much more than almost any other park because of its cavernous outfield. In San Francisco, Imanaga’s problems with the fly ball would not be amplified to the level they would be in New York, Boston, or Chicago, and would allow for Imanaga to have the most success of any of those locations as his greatest concern will be somewhat mitigated. If he ends up somewhere else, he should still find success, as each team’s pitching development departments will work hand-in-hand to get the most out of his interesting skill set.

Where will Imanaga sign?

San Francisco Giants
New York Mets
Boston Red Sox
Chicago Cubs

Relevant Work:

Brozdowski, L. (2023). YouTube. From https://youtu.be/rcB8NtHA9gw?si=KPUjJLdo_Bz8Jy1k.

Clemens, B. (2023, November 9). 2024 Top 50 MLB Free Agents. FanGraphs . https://blogs.fangraphs.com/2024-top-50-mlb-free-agents/

Kenta Maeda. 1.02 Essence of Baseball-DeltaGraphs. (n.d.-a). https://1point02.jp/op/gnav/player/stats/player_stats_ps.aspx?pl=999900206

Kodai Senga. 1.02 Essence of Baseball-DeltaGraphs. (n.d.-b). https://1point02.jp/op/gnav/player/stats/player_stats_ps.aspx?pl=999900797

Leighton, A. (2023, December 4). Japanese Left-Hander Shota Imanaga Will Have Plenty of MLB Suitors. Just Baseball. https://www.justbaseball.com/mlb/japanese-left-hander-shota-imanaga-will-have-plenty-of-mlb-suitors/

McGrattan, O. (2023, March 10). Stuff+, Location+, and Pitching+ Primer. FanGraphs. https://library.fangraphs.com/pitching/stuff-location-and-pitching-primer/

Shohei Ohtani. 1.02 Essence of Baseball-DeltaGraphs. (n.d.-c). https://1point02.jp/op/gnav/player/stats/player_stats_ps.aspx?pl=201300037

Shota Imanaga. 1.02 Essence of Baseball-DeltaGraphs. (n.d.-d). https://1point02.jp/op/gnav/player/gamelog/player_gamelog_ps_standard.aspx?sn=2023&pl=201600015&snf=0&snt=0&cp=101

Shota Imanaga. SPAIA. (n.d.). https://spaia.jp/baseball/npb/player/1500061

Sports Reference, LLC. (n.d.). Shota Imanaga Japanese Leagues Statistics. Baseball Reference. https://www.baseball-reference.com/register/player.fcgi?id=imanag000sho

Tew, B. (2023, November 29). NPB Free Agent Scouting Report: Shōta Imanaga. Sports Info Solutions. https://www.sportsinfosolutions.com/2023/11/29/npb-free-agent-scouting-report-shota-imanaga/

Yoshinobu Yamamoto. 1.02 Essence of Baseball-DeltaGraphs. (n.d.-e). https://1point02.jp/op/gnav/player/stats/player_stats_ps.aspx?pl=201700112