Yuki Matsui isn't the most talked-about free agent to make the jump from Nippon Professional Baseball to MLB this offseason, but the Tohoku Rakuten Golden Eagles closer who signed a 5-year deal with the Padres may be the most interesting.

Here are three reasons the 28-year-old left-hander -- who's coming from the same team Masahiro Tanaka did when he signed with the Yankees in 2014 -- would be an intriguing addition for San Diego.

1) He'll be one of the shortest pitchers in recent MLB history

Pitchers are tall. Matsui is not. He's listed at just 5-foot-8 and 165 pounds, which would make him the third-shortest active pitcher in the Majors today, after 5-foot-6 Clayton Andrews and 5-foot-7 Marcus Stroman.

Since 2015, there have been only five MLB pitchers who are 5-foot-8 or shorter. Since 2010, there have been only eight. And going back to 2000, there have been only 14. Of those, the only really effective pitchers are the two-time All-Star Stroman and former Royals reliever Tim Collins.

Aside from Stroman, nearly the entire group is left-handers like Matsui; a pitcher who doesn't have prototypical height is most likely to make it to the Majors if he's a lefty specialist.

Of course, Matsui's height didn't stop him from being a lights-out closer in NPB. He notched 39 saves with a 1.57 ERA and 11.3 strikeouts per nine innings last season and averaged 32 saves with a 1.42 ERA and 12.7 K/9 over the last three.

2) His fastball plays up for his size

He might be small, but Matsui has a big league-caliber fastball. His four-seamer sits at around 92-94 mph, typical for an MLB lefty reliever, but it can touch 96 mph -- impressive for a 5-foot-8 lefty.

Here's maybe the most interesting thing about Matsui's fastball: It's the type of high-spin, rising fastball that will play up and can generate swings and misses even at average velocity. That's a big reason for Matsui's 36% strikeout rate in NPB over the last three seasons.

Matsui pitched for Samurai Japan in the World Baseball Classic this year and threw an inning against Korea with Statcast tracking in place, so we got a small bit of data on his fastball there. (He also pitched in the 2017 Classic, but there was no pitch tracking for his outings in that tournament.) Matsui's four-seamer averaged 92 mph with a 2,471 rpm spin rate. That's high -- the MLB average four-seam spin rate was 2,283 rpm in 2023 -- and the vertical movement data for Matsui indicates that his fastball was inducing strong rise as a result.

Matsui got a pair of whiffs on his four-seamer against Korea in the WBC: one against former MLB left fielder Hyun Soo Kim at 92 mph and 2,562 rpm, the other against Hae-Min Park at 91 mph and 2,419 rpm.

He also retired Korean superstar Jung Hoo Lee -- who just signed a $113 million deal with the Giants -- on a four-seamer at 93 mph and 2,444 rpm, which Lee lined out against.

3) His lefty splitter will give MLB hitters an uncommon look

Like many of the top pitchers from Japan, Matsui deploys a nasty splitter as his No. 1 secondary pitch. (He also has a slider, but the splitter is what's of note here.)

Matsui's splitter sits in the high 80s. In his World Baseball Classic appearance, the split averaged 88 mph with 31 inches of drop and 12 inches of horizontal break. He used it to strike out Kim to cap off his inning of work.

There's been a small influx of wipeout splitters in the Major Leagues in recent seasons -- many of them brought by Japanese pitchers like Shohei Ohtani, Kodai Senga and Tanaka. But what there isn't a lot of in the Majors is lefty splitters.

While splitters are on the rise around the Major Leagues, those splitters are overwhelmingly thrown by right-handed pitchers -- 96% of the splitters thrown in MLB in 2023 were by righties, and only 4% of them were thrown by lefties.

Of the 83 pitchers who threw any splitters in 2023, 75 were righties. There were only eight lefties in all of MLB who threw a splitter, with the biggest names being Aroldis Chapman and Clayton Kershaw (who replaced his rarely used changeup with a split-change) but the only really frequent lefty splitter user being Chasen Shreve.

But now there could be two more good ones entering the big leagues from NPB: Matsui's and Sh¨­ta Imanaga's. That's what could give Matsui his biggest competitive advantage against MLB hitters. His best out pitch is something that they almost never see.