NPB Players To Watch: September

The 2023 regular season is approaching its final stages in the NPB. Here’s the latest on the players we’ve been keeping track of at MLBTR. If you need a refresher on more specific player profiles, check out the first edition of the series.

Let’s get to it!

(Stats are as of September 13th)

Players likely available in the 2023 offseason (most rumored or have publicly announced desire to play in MLB)

1. Yoshinobu Yamamoto, Orix Buffaloes

Yamamoto continues to show us why he’s undoubtedly the best pitcher in NPB. The 25-year-old right-hander just tossed his second career no-hitter against the Chiba Lotte Marines this past weekend, in front of scouts/executives of 12 MLB ball clubs, including Yankees GM Brian Cashman.

It feels like a long time ago when I wrote that Yamamoto was having a “slow” start to the season by his standards, with a 2.35 ERA in his first 38 ⅓ innings. Yamamoto has shifted into a different gear since May. Yamamoto hasn’t given up an earned run in six consecutive starts, since the beginning of August. He’s currently on a 42-inning streak without an earned run allowed.

In his 20 starts in 2023, the Orix Buffaloes ace has a 1.26 ERA, striking out 26.2% of hitters and walking just 4.3%, and a 1.86 FIP in 143 frames. That 1.26 ERA is good enough for the lowest ERA in NPB since Masahiro Tanaka’s 1.27 ERA in 2011. Yamamoto is once again on pace to claim the Pacific League pitching triple crown (ERA, strikeouts, wins).

At age 25, Yamamoto is showing no signs of slowing down and continues to evolve. He notably tweaked his delivery last offseason to more of a slide-step style. Despite the “slow start”, it’s safe to say that the change has paid off, as Yamamoto has raised his average fastball velocity to 95.56 mph (152.9 km/h) compared to 94.9 mph (151.9 km/h) in 2022. In addition to his consistency, strikeout stuff, and ability to pitch deep into games, another development in Yamamoto’s game is his ability to keep the ball in the park. Yamamoto has allowed just two homers all season (he gave up between six and eight homers per season since his first full season as a starting pitcher in 2019).

2. Shota Imanaga, Yokohama DeNA Baystars

It was reported last week that the Yokohama DeNA Baystars lefty will be posted this off-season, as many in Japan predicted last off-season. The 30-year-old southpaw had his best month in July but got roughed up in August with a 5.27 ERA. He had a bounce-back outing earlier today against the Chunichi Dragons, tossing eight innings of one-run ball and striking out eleven, with the sole run coming from a solo homer. His season numbers are still strong, with a 2.71 ERA, 29.96% strikeout rate, and 3.9% walk rate in his 20 starts.

Although his ERA is not as good as 2022 (2.26), Imanaga’s strikeout rate at 29.9% is a career-best. The Baystars ace notably increased his average fastball velocity in the past few seasons. It now sits around 92.2mph (147.5 km/h), compared to 90.8 mph (145.3km/h) in 2021. While Imanaga’s arm is not overpowering, the combination of his command and strikeout stuff allows him to rack up strikeouts. 

3. Yuki Matsui, Tohoku Rakuten Golden Eagles

The 27-year-old left-handed closer for the Eagles continues to be one of the best relievers in NPB. Despite his young age and being converted to a starter on a few occasions during his career, Matsui is one of the most accomplished closers in the history of NPB. The southpaw became the ninth NPB pitcher in history to reach 200 career saves and was the youngest player to ever reach that mark. On the season, he has the second most saves in NPB with 33. He’s been nothing but reliable, with strong numbers to back it up; posting a 1.55 ERA, 33.7% strikeout rate, and 5.1% walk rate in 49 appearances. 

Matsui officially earned his overseas free agent rights earlier in the year, giving him the ability to sign with an MLB team without going through the posting system. The Eagles southpaw still hasn’t made clear what his plans are beyond 2023. 

As I wrote in the first edition of the series, Matsui’s struggle to adapt to the WBC ball, which is closer to the MLB ball, may play a role in his MLB evaluation. If MLB offers aren’t enticing enough, he may very well choose to stay in NPB and attempt to break the NPB save record. 

4. Kona Takahashi, Saitama Seibu Lions

Takahashi continues to prove that his career-best season in 2022 was not a fluke, posting a strong 2.31 ERA in 22 starts, the eighth highest among qualified starters in the entire NPB. He’s fanned hitters at an 18.8% rate and walking hitters at a 7.7% rate. 

The 27-year-old righty missed a few starts in August because of an illness. He struggled in the first two starts after his return, clearly still regaining his health and conditioning. He bounced back and tossed six shutout innings this past weekend, in front of MLB scouts. He continues to make improvements and his average fastball velocity has improved dramatically since he entered the league, which should make him more intriguing to MLB teams. 

Takahashi made his MLB aspirations clear last offseason, but it’s unclear if he’ll be posted by the Lions. 

5. Naoyuki Uwasawa, Hokkaido Nippon Ham Fighters

Naoyuki Uwasawa has had himself another solid season for the Fighters, posting a 2.84 ERA, with an 18.1% strikeout rate and 7.7% walk rate in 158 ⅓ innings, the most innings pitched in all of NPB. 

Sports Hochi reported that scouts from the Angels, Royals, Rangers, Diamondbacks, Reds, and Cubs attended his September 2nd, so MLB teams are keeping tabs on the 29-year-old right-hander. Unfortunately, there may be a Kohei Arihara-sized cloud hanging over Uwasawa’s MLB dreams. Uwasawa doesn’t have an overpowering arm with his average fastball velocity sitting around 90.8 mph. He also does not boast strikeout stuff, while not having the same command that Arihara had when he was coming to MLB (although Arihara himself was wild during his Rangers tenure). 

Younger stars to keep an eye on

1. Roki Sasaki, Chiba Lotte Marines

Sasaki was on pace for a historic season rivaling Yamamoto’s, before he was diagnosed with a left oblique muscle tear which sidelined him at the end of July. The 6-foot-4 hurler was expected to miss the remainder of the 2023 regular season, but made a surprisingly quick recovery and returned over the weekend. Sasaki was limited to three innings since he skipped a rehab start, but still showcased his lively arm, with his signature fastball sitting between 98mph and 100mph. The Marines will likely not overextend their star right-hander, so he will be carefully managed for the remainder of the season. 

On the season, Sasaki has a 1.53 ERA, an unbelievable 40% strikeout rate, a 4.8% walk rate and 88 innings in his 14 starts. There is no doubt about Sasaki’s talent and natural frame at 6’4″ and 203 pounds. The only thing Sasaki has left to “prove” is his durability, and showcasing that he can pitch multiple full seasons. There is plenty of time for him to prove that, since he’ll likely be posted in the 2026 offseason at the earliest, barring any surprise requests.

2. Munetaka Murakami, Tokyo Yakult Swallows

Murakami has shrugged off most concerns and has re-established himself as one of the premier power hitters in NPB. Although he has had, by his standards, the statistically worst season since his rookie season in 2019, Murakami is still slashing a solid .253/.372/.497 with 28 homers, 77 RBIs, and a .869 OPS. 

Murakami did address his early season slump in an August interview, where he said he lost his way a little bit while training with the other Japanese stars in the lead-up to the WBC. He said that he got distracted trying to incorporate the training regimen of players like Shohei Ohtani, Masataka Yoshida, and Yu Darvish and did not address his swing as much as he should have. 

While he does have a great walk rate at 18.1%, Murakami is still striking out at an alarming 34.5% rate. He also struggles to hit righties, hitting just .209 against them. He still needs to make improvements with his defense at third base, as he has an NPB-worst 20 errors. This season is obviously far from Murakami’s best, but a down year may allow him to come back even stronger next season.

Murakami signed a three-year deal last offseason that came with a reported guarantee that he will be posted in the 2025-2026 offseason. 

3. Kazuma Okamoto, Yomiuri Giants

Okamoto’s name came up in headlines last week, after it was reported that he was on the radar of several MLB teams. Okamoto is in the midst of a career-year, with a slash line of .293/.386/.611 with 90 RBIs and an NPB-leading 38 homers and .997 OPS. He has an 18.9% strikeout rate and a 12.2% walk rate. He was unstoppable in August, slashing .318/.422/.812, blasting 12 homers and driving in 25 runs. 

Okamoto has hinted at interest in a potential MLB move, but he isn’t set to be a free agent until the 2026-2027 offseason. The 6’1″, 220-pound slugger is a career .275 hitter with 182 homers, hitting at least 30 homers in every season since becoming a full-time starter in 2018. The Giants slugger has hit 30 homers for six consecutive seasons, which speaks to his durability and consistency.

The Giants are traditionally against the posting system. The only two players they allowed to be posted were Shun Yamaguchi and Tomoyuki Sugano, and both were unique situations. Yamaguchi was given permission because he made it a part of his free agency deal when signing for the Giants from the Baystars in 2016. Sugano was given special permission to enter the posting system, because he refused to join the Nippon Ham Fighters when he was originally drafted in 2011 and he held out for an entire season before being drafted by the Giants in 2012 (and his uncle is Giants manager Tatsunori Hara, which may have played a role).

As expected, the ball club has denied any conversations regarding Okamoto’s potential move, with executive Atsunori Otsuka saying “We’ve heard he has MLB aspirations, but we’ve never had direct discussion with him about that. We typically don’t accept posting, and want our players to earn their overseas rights. It was the same with Hideki Matsui.”

Honorable Mentions

The following players have either expressed their desire to play in the big leagues, been rumored by Japanese media, or have drawn interest from MLB scouts but have factors (age, team stance on posting system) preventing a potential move. Other NPB top performers are also on the list.

Shosei Togo, right-handed starting pitcher, Yomiuri Giants; Taisei Ohta, right-handed reliever, Yomiuri Giants; Hiroto Takahashi, right-handed starting pitcher, Chunichi Dragons; Kaima Taira, right-handed starting pitcher, Saitama Seibu Lions; Atsuki Yuasa, right-handed reliever, Hanshin Tigers; Shinnosuke Ogasawara, left-handed starting pitcher, Chunichi Dragons; Shunpeita Yamashita, Orix Buffaloes; Atsuki Taneichi, right-handed starter, Chiba Lotte Marines. Liván Moinelo, left-handed reliever, Fukuoka Softbank Hawks. Raidel Martinez, right-handed reliever, Chunichi Dragons. (Moinelo and Martinez will have to defect their homeland, Cuba, to join MLB)