Roki Sasaki and Main League Baseball: How efficient would his pitching arsenal be?

Roki Sasaki is a stud. In all probability.

He first attracted stateside consideration within the 2023 World Baseball Traditional, when he sat 100 mph on the fastball and introduced his presence with authority. However Sasaki, 23,  has been placing up some bonkers numbers in Japan, with a 2.02 profession ERA, and there’s an opportunity he comes over to Main League Baseball by way of the posting course of this offseason. Everybody must be , and just some could have the worldwide money to step to the desk — the Chiba Lotte Marines may maintain him for an additional two years, and gamers beneath 25 are topic to worldwide bonus pool guidelines — however that doesn’t imply we all know all the things there’s to learn about Sasaki as a pitcher.

To some extent, there’s at all times a stability between what a crew is aware of and what it doesn’t learn about a free agent. Even with a mid-career place participant who has performed Main League Baseball for his complete skilled profession, there are issues the buying crew can’t know. That’s maybe why it’s most likely true that groups get extra manufacturing after they re-sign their very own gamers than after they poach a participant from one other crew. The belief is that they know extra concerning the participant they already had, issues like make-up and well being.

When signing a pitcher from one other league, that stability is skewed towards the unknown. Not solely have they been taking part in in a completely completely different league, however they’re pitchers, and pitchers are topic to extra season-to-season swings in manufacturing. Pitching prospects nonetheless find yourself with worse outcomes than hitting prospects, and even a pitcher as thrilling as Sasaki is nearer to a prospect than a longtime major-league pitcher.

That stated, Sasaki has pitched in entrance of pitch-tracking machines, has performed at one of many highest ranges in baseball exterior of the large leagues, and has given us some perception into the place he stands health-wise. We will comply with the crumb path to get a way of how groups is perhaps considering of him throughout a potential posting interval. His availability is just not etched in stone, however possibly we will perceive his expertise if we use the trendy instruments of pitching evaluation.

The stuff

Sasaki threw on the World Baseball Traditional in 2023, giving us pitch motion and velocities that may assist us put the bodily traits of his pitches on the identical footing as pitchers from MLB. There, he had a superb 111 Stuff+ total, which had him within the high 10 amongst starters at that match, and would have put him within the high 10 amongst certified big-league starters this previous season. He was behind Cristian Javier and Sandy Alcantara on the WBC, however forward of Jesús Luzardo and Pablo López.

One factor we learn about that match is that the gamers have been amped to be there. They threw more durable fastballs in shorter outings. The common starter who pitched within the WBC after which once more within the large leagues over the previous two years misplaced about 5 factors of Stuff+ within the transition. Somebody like Shota Imanaga, who had an excellent season for the Chicago Cubs, misplaced much more as a result of he was used as a reliever. Sasaki averaged 100 mph on his fastball with nice two-plane motion and by Stuff+, he had the very best fastball amongst starters not named Shohei Ohtani in that match.

He’s misplaced a few of that velocity already in Japan, averaging 98.9 mph in 2023 after which 96.9 this previous season. That velocity might be fairly vital. Sasaki had 17-plus inches of induced vertical motion and 13 inches of horizontal motion within the WBC. At 98-plus mph, his fastball comps to these numbers are hard-throwing relievers like Kansas Metropolis Royals nearer Lucas Erceg and New York Mets setup man Ryne Stanek, and possibly Hunter Greene amongst starters. At 96-plus, the comps are rather less thrilling: Cleveland Guardians starter Gavin Williams and reliever Yimi García have some commonalities with their fastballs. And, in keeping with Lance Brozdowski, Sasaki additionally misplaced a few inches of trip on the fastball in 2024 in Japan. It’s a extremely good fastball both approach, however there are some indications it’s transferring within the fallacious path.

His slider was an 87 mph gyro slider, that means it’s a bullet slider and not using a ton of motion. That WBC slider would comp nicely to sliders thrown by Seattle Mariners nearer Andrés Muñoz and Pittsburgh Pirates starter Mitch Keller. It was right down to 83.6 mph this previous season, although, and that’s under the 85 mph threshold for excellent gyro sliders, and now it appears extra like Royals starter Brady Singer’s slider. Nonetheless an asset, however you could sense a theme right here.

Splitters are arduous to get a deal with on in small samples, however in keeping with this NPB pitch profiler, Sasaki’s splitter bought a whiff a whopping 57 % of the time batters swung final 12 months (25 % of all pitches). Solely Cincinnati Reds reliever Fernando Cruz this 12 months had a greater whiff share in MLB, and Imanaga ended up relying immensely on his splitter with a 42.9 % whiff charge this previous season.

Sasaki’s splitter passes the attention take a look at:

Roki Sasaki’s splitter from an NPB sport early final season. This one was 91mph, and you’ll see the large, four-seam grip on the closeup. He kills a outstanding quantity of spin for how briskly the pitch is. pic.twitter.com/u9fqQBqZTr

— Lucas (@DBITLefty) March 20, 2023

It’s top-shelf stuff from Sasaki, on par with any pitcher who has come over from Japan, even when it’s down a bit.

The outcomes

Two years in the past, Sasaki had a season for the ages. In 2022, he sported a 2.02 ERA with 173 strikeouts towards solely 23 walks in 129 1/3 innings. Simply unconscionable. He adopted that up with a season that was even higher by charges and strikeouts (1.78 ERA, 135 strikeouts), however shorter on innings (91) as a result of an indirect harm. This 12 months, bouts of upper-body fatigue and arm soreness held him to 111 innings with a 2.35 ERA however a diminished Okay charge — solely 129 strikeouts. This follows the pattern established above, the place he simply had obscene stuff at age 20 in Japan, after which began to fall off that peak to some extent.

Nonetheless, when you use three-year numbers to seize each the height and what got here after, he profiles very well in a key statistic. As a result of NPB doesn’t have as many energy hitters, it’s robust to port over issues like ERA or house run charge. For instance, Yoshinobu Yamamoto gave up two (two!!) homers in 171 innings in Japan in 2023 earlier than coming over and giving up seven in 90 innings towards main leaguers this 12 months.

As an alternative, if we use strikeouts minus walks, we’ve a stat that has achieved a superb job predicting the success of pitchers coming over from Japan. 9 pitchers have come over to begin at the very least 15 video games in MLB who had at the very least an 18 % strikeout-minus-walk charge within the three NPB seasons previous their transfer. There are solely two pitchers on the checklist who depend as disappointments. 9 pitchers additionally came visiting and had a strikeout-minus-walk charge beneath 18 % and began 15-plus video games in MLB. Hideo Nomo, Yusei Kikuchi, Hisashi Iwakuma and Kenta Maeda are the success tales on that checklist.

Look the place Sasaki sits amongst his friends.

Once more, although, Sasaki has fallen off some. He had a strikeout-minus-walk charge above 30 % for 2 years, after which final 12 months it fell to 21.6 %. You can be involved concerning the declining stuff and outcomes, certain. However that 21.6 % charge would’ve been fifth on this checklist, between Masahiro Tanaka and Imanaga. Nonetheless fairly good.

The attention of the beholder could have an outsized say within the negotiations. Both Sasaki is an oft-injured pitcher with already declining stuff, or he’s bought a few of the greatest stuff we’ve seen from a pitcher coming over even after that decline. Given the character of the contract negotiations, a crew that convinces Sasaki that they can assist him get again to 2022 when it comes to well being and stuff is perhaps the crew that seals the deal.

(Photograph of Roki Sasaki pitching within the World Baseball Traditional on March 20, 2023: Eric Espada / Getty Photos)