With This Japanese Ace, the Ghost Stories Are True

As the United States prepared to face Japan in the knockout stage at the Tokyo Olympics in 2021, Nick Martinez issued a warning to his peers.

“Don’t swing at the fork,” Martinez, now a star relief pitcher for the San Diego Padres, told them. Martinez was referring to Kodai Senga of Japan and his forkball, which is nicknamed the ghost fork.

Martinez had spent four seasons in Nippon Professional Baseball in Japan, as both a teammate and an opponent of Senga’s. He knew how haunting the ghost fork could be, yet his fellow Americans could not lay off the pitch.

“Our guys just kept swinging at it, swinging at it, swinging at it,” Martinez said. “I was like: ‘Guys, I told you not to swing at it. What’s going on?’ They’re like: ‘Yeah, but it looks right there and then it’s gone. We don’t see it.’”

Senga struck out five over two scoreless innings in a 7-6, 10-inning win for Japan. A few days later, he added a blank frame against the U.S. team in the gold medal game, which Japan won. The two notable performances had people talking about his baffling pitch, which seems to disappear to batters just as it gets to home plate. And unlike Daisuke Matsuzaka’s gyroball, which proved to be a tall tale, or perhaps just a slider, Senga’s forkball, according to some of the people who have seen it, is a devastating weapon that delivers on the hype.

After more than a decade with the Fukuoka SoftBank Hawks, with whom he earned five Japan Series titles (he was not on the postseason roster for a sixth title, which the team won in 2014), Senga will chase a World Series ring with the Mets. A coveted international free agent, Senga recorded a 2.59 E.R.A. over 1,089 innings in his home country and was a part of the Mets owner Steven A. Cohen’s off-season spending spree. Senga, 29, signed a five-year, $75 million deal in December and held his introductory news conference just before the holidays.

“Hi, I am Kodai Senga of the New York Mets,” the right-hander said in English after donning his new team’s jersey for the first time. “I’m very happy and excited to be in the Big Apple and join such a great team.”

The excitement for fans, teammates and even opponents is palpable as everyone waits to see how Senga will perform in the United States. They are excited, too, to see his ghost fork — that is, if they can track it.

How quickly he will adjust to life in the United States remains an open question. While Masahiro Tanaka was an instant star for the Yankees in 2014, before he was slowed by injuries, and Yu Darvish and Shohei Ohtani have been models of sustained success, other Japanese aces like Hideo Nomo and Matsuzaka mixed bad games with good ones before finding their footing.

The move to Major League Baseball presents challenges for any pitcher. But for Senga, who did not get a chance to play in Japan’s prestigious high school baseball tournaments and started his professional career as a developmental league draft pick, rising to a challenge is nothing new.

Rick van den Hurk, a former big league pitcher and a SoftBank teammate of Senga’s from 2015 to 2020, likened Senga’s path to an undrafted player in the United States who reaches the majors.

“Very few of those players ultimately make it to the N.P.B. level, and very few of them become stars,” Mets General Manager Billy Eppler said in his opening remarks at Senga’s news conference. “So he’s constantly working to improve. He fought his way to become a star and a championship level pitcher.”

Van den Hurk said Senga’s path “tells a lot about his character,” and Martinez said it was no coincidence that a team with World Series aspirations would want to add Senga to its rotation.

“They got a winner,” said Martinez, who joined the Hawks in 2021 after three seasons with the Hokkaido Nippon-Ham Fighters.

Martinez added that Senga displayed “leadership qualities” in the clubhouse, and van den Hurk highlighted Senga’s sense of humor and sociability. Senga would drop one-liners in English so that he could interact with his foreign teammates, and van den Hurk believes those jokes will make him a hit in the Mets’ clubhouse as he continues to learn the language.

The adjustments Senga will have to make go beyond learning a language and facing new batters.

David Robertson, a right-handed reliever who signed with the Mets this off-season, competed against Senga in the Olympics. He was also there for Tanaka’s first season in the Bronx, and was a teammate of outfielder Seiya Suzuki, who made his major league debut with the Chicago Cubs last season. Based on his experiences with those players, Robertson said one issue is that the weather is typically warmer in Japan than it is in some of M.L.B.’s northern cities, especially early in the season, and that many N.P.B. teams play in domes.

It will be hard for Senga to deal with cold weather “right out of the gate,” Robertson said.

An M.L.B. job also comes with more travel, and most teams use five-man rotations, rather than six, the rotation in Japan. On the field, Senga will have to acclimate to a harder pitching mound and a larger baseball which doesn’t feature the tack Japanese pitchers are accustomed to. Between that and the weather, Mets fans may want to consider giving him a grace period, especially because his top pitch is dependent on grip.

“He’ll pitch in one or two games and then realize what he needs to do to get himself through those innings and games,” Robertson said. “I’m sure he adjusts very well because you can’t pitch that well and be that good at a sport without being able to adjust on the fly.”

Martinez went as far as wondering if Senga’s strikeout numbers would improve in the United States, as Japanese hitters, in his experience, are more prideful about putting the ball in play than some of their all-or-nothing M.L.B. counterparts.

“It’s not like playing in Japan is playing in the minor leagues or playing in college,” Robertson said. “It’s the big leagues over there, too. Same game, different level, but I don’t see any issues with that.”

Senga comes with what is a warning label to some people because of his reliance on a forkball — regardless of how great it might be.

A pitch known to produce results in the right hands — it helped put Gaylord Perry and Jack Morris in the Hall of Fame and made Dave Stewart one of baseball’s greatest postseason pitchers — the forkball also has a reputation for damaging arms. But Stewart, who has spent time as a player, executive, coach and agent, doesn’t put much credence in those concerns.

“Any pitch that you throw incorrectly creates a problem for your arm,” said Stewart, who once won 20 or more games in four consecutive seasons, all with heavy use of a forkball.

Stewart said that a loose wrist is key to success with a forkball, and that the mechanics of the pitch should mimic those of the player’s fastball. He said Senga’s ghost fork does exactly that.

“Everything has to look the same,” Stewart said. “The fastball has to look the same, and his does. He’s got great deception. And then he’s got tremendous downward movement, which is what makes the pitch even more successful.”

Stewart began searching for Senga’s highlights as expectations of a switch to the majors grew stronger. He came away just as impressed as those who have seen the pitch firsthand.

“All of a sudden, it would fall off the table, go straight down,” Robertson said of the forkball, echoing Stewart’s sentiment that the pitch looks exactly like Senga’s high-90s fastball. “It’s an electric pitch.”

Van den Hurk said the depth, tunneling and late break of Senga’s signature pitch can demoralize opponents.

“And then he controls it very well, and that’s very impressive for a forkball,” van den Hurk said. “Forkballs could be quite hard to control, and it seems like he has good control over it, even in nonfastball counts.”

As for Senga, he is not engaging with the hype. Asked how he developed his ghost fork, he did not waste any words, or offer any clues of how other pitchers could replicate it.

“Practice,” he said.

Martinez, who tried to recruit Senga to San Diego, said the Mets signed a difference-maker.

“It’s a great pickup, and I’m excited to see him pitch,” Martinez said. “I wish him the best, except against us.”