Kodai Senga is unlike any other MLB free-agent pitcher
The MLB free-agent pitching market this offseason can be best understood as falling into two distinct tiers.
At the very top are three super-aces: a future first-ballot Hall of Famer in Justin Verlander, the best pitcher on earth (when healthy) in Jacob deGrom and arguably MLB's best left-handed starter in Carlos Rodón. Within the second tier exists a wealth of mid-rotation options who are immensely valuable, though not as overwhelmingly dominant and franchise-altering the way the top three are. This is Jameson Taillon, Nathan Eovaldi, Taijuan Walker and Chris Bassitt, among others.
In between those tiers, though, exists one fascinating mystery-box candidate in right-hander Kodai Senga. Senga has delivered super-ace-level performance, albeit in a league on the other side of the world.
Not every player who comes over from Japan's NPB arrives with a parade of hype. Senga isn't a once-in-a-lifetime Shohei Ohtani-type talent or even on the level of Yu Darvish when he arrived a decade ago, but there's still a ton of reason to be excited. He's coming off another excellent season — posting a 1.94 ERA with 156 strikeouts across 144 innings for the Fukuoka Softbank Hawks in NPB, the top league in Japan. Turning 30 in January, Senga is younger than every other starting pitcher available besides Zach Eflin, adding to his appeal for teams reluctant to commit big dollars to pitchers already nearing their mid-30's. Though NPB is not MLB, his decade-long track record of excellence in what is widely considered the world's second-best league has a huge group of teams targeting him as one of the most appealing players on the entire free agent market.
It's easy to look at the tremendous statistics and dream big about Senga's potential atop an MLB rotation, but there are many ways a pitcher can compile a sub-2 ERA. So how does he do it? What kind of pitcher is Senga?
The first thing to know is that, like many Japanese aces before him, Senga relies heavily on an incredible splitter to induce both whiffs and weak contact. Senga's splitter in particular — which he threw about 20% of the time at an average of 85 MPH — is of the forkball variety and has been dubbed by the likes of Pitching Ninja as the "ghost fork."
While splitters are awfully common among Japanese pitchers, where Senga has truly stood out among his NPB peers is his easy plus velocity, that fits right into the familiar flamethrowers of MLB. His heater averaged about 96 MPH in 2022, tops among all qualified NPB starters. Along with an impressive four-seamer and fantastic forkball, Senga also has a high-80s cutter and low-80s slider to round out his repertoire. All together, we can take Senga's arsenal and compare it to the likes of those already succeeding in MLB to paint a picture of how he may attack big league hitters in 2023.
Ten MLB starting pitchers used a splitter at least 10% of the time in 2022. Of those 10, six primarily use a four-seam fastball instead of a two-seamer (sinker) like Senga: Kevin Gausman, Tony Gonsolin, Tyler Mahle, Nathan Eovaldi, Jake Odorizzi and Shohei Ohtani. Ohtani jumps out for obvious reasons, but let's put him aside as he only uses his splitter about 12% of the time and relies much more heavily on his breaking pitches:
Shohei Ohtani
- Fastball: 27.6% – 97 MPH AVG
- Splitter/forkball: 12% – 89 MPH AVG
- Cutter: 9.1% – 91 MPH AVG
- Slider: 39.1% – 85 MPH AVG
- Curveball: 8.6% - 78 MPH AVG
Odorizzi also falls below the 20% splitter mark with more significant cutter usage instead. The other four, however, have repertoires that much more consistently resemble that of Senga's:
Kodai Senga
- Fastball: 44.3% – 96 MPH AVG
- Splitter/forkball: 20.8% – 85 MPH AVG
- Cutter: 18.7% – 88 MPH AVG
- Slider: 11% – 83 MPH AVG
Kevin Gausman
- Fastball: 48.8% – 95 MPH AVG
- Splitter/forkball: 34.8% – 85 MPH AVG
- Slider: 14.5% – 84 MPH AVG
Tony Gonsolin
- Fastball: 39.1% – 93 MPH AVG
- Splitter/forkball: 27.5% – 84 MPH AVG
- Slider: 21.5% – 88 MPH AVG
- Curveball: 11.9% – 81 MPH AVG
Nathan Eovaldi
- Fastball: 38.4% – 96 MPH AVG
- Splitter/forkball: 20.9% – 88 MPH AVG
- Cutter: 10.1% – 91 MPH AVG
- Slider: 12.5% – 86 MPH AVG
- Curveball: 18.5% - 78 MPH AVG
Tyler Mahle
- Fastball: 51.6% – 93 MPH AVG
- Splitter/forkball: 24.0% – 85 MPH AVG
- Cutter: 12.9% – 86 MPH AVG
- Slider: 11.4% – 84 MPH AVG
Gausman signed a five-year, $110 million contract with Toronto a year ago entering his age-31 season and immediately delivered another impressive campaign in 2022. Gonsolin just had a huge breakout season in which he posted the second-lowest ERA in MLB among pitchers with at least 100 innings pitched. After his heroics in the 2018 postseason, Eovaldi signed a four-year, $68 million contract entering his age-29 season and is now hitting the open market again coming off a down year. And Mahle was just traded from Cincinnati to Minnesota at the deadline for a strong prospect package.
The degree to which these splitter specialists have succeeded in recent years should be a good sign for Senga as he makes the jump and could hint at what teams are willing to pay in free agency. There's always added intrigue with those coming over from international leagues, but signing them also comes with greater risk. We've seen NPB stars struggle just as we've seen them thrive. Senga's track record and impressive arsenal suggests an excellent chance of finding quick success in the big leagues, but we won't know his ultimate ceiling until he's actually here trying to reach it. In addition to all the challenges any NPB player faces in adjusting not just to the challenges of competing in MLB but life in a new country and culture, Senga's success will be dictated by the adjustments he makes as he settles in against the best competition the world has to offer. His talent isn't remotely in question, though.
The reporting surrounding Senga's free agency has indicated that his market includes many teams, but history tells us that certain franchises have been far more successful at recruiting NPB stars to MLB than others. Since and including Hideo Nomo in 1995, 59 players have signed with MLB teams following extended careers in NPB — 42 pitchers, 16 hitters and one Shohei Ohtani. These players range from future first-ballot Hall of Famers like Ichiro to brief big-league cameos for relievers like Kazuhisa Makita and Kyuji Fujikawa.
The Mets have signed the most with eight, followed by the Mariners and Dodgers, who are tied at six, and the Yankees, Red Sox and Rangers at four apiece. That means six teams account for over half of NPB-to-MLB signings over the last three decades. In fact, five teams have still never signed a player straight out of NPB: the Astros, Marlins, Nationals, Phillies and Rockies. Each of them has rostered a Japanese player at some point, but only after they had already played for another MLB team. This isn't to say it's impossible for those not in the top six like San Diego and San Francisco — who are rumored to be hard after Senga — to ultimately land him, but it's difficult to deny that the same few teams have had the most success signing Japanese players.
Regardless of the journey he has taken to get here, Senga represents a relatively high-risk, high-reward starting pitching option unlike anyone else on the market. Some teams will focus on bringing in pitchers in the second-tier who are far safer bets to continue delivering league-average or slightly better performance as they have for the past decade in MLB — including those like Eovaldi, who may offer a similar profile (and variance!) with an actual big-league track record in tow. But the possibility of greatness for Senga has teams pursuing the potential for so much more, and I can't wait to see where his next chapter will be written.
Jordan Shusterman is half of @CespedesBBQ and a baseball writer for FOX Sports. He has covered baseball for his entire adult life, most notably for MLB.com, DAZN and The Ringer. He's a Mariners fan living in the Eastern Time Zone, which means he loves a good 10 p.m. first pitch. You can follow him on Twitter @j_shusterman_.