Milliken: Could Kazuma Okamoto be the Red Sox solution at first base?

It’s not as always easy to decipher what Craig Breslow is trying to convey through his typical word salad, but at the Red Sox end of season press conference a few weeks back, he made it clear they weren’t planning to pencil Triston Casas in at first base with his rehab situation and injury history. That’s led to a daily discussion across almost every Red Sox forum about which first base options the front office should consider, especially as they search for power and how to replace an elite bat like Rafael Devers. Some have fallen in love with a masher like Pete Alonso, others like Josh Naylor’s hitterish profile, and there are now even rumors of Bryce Harper potentially being on the trade block, but the name that has frequently caught my attention is NPB stud Kazuma Okamoto. 

Okamoto isn’t generating as much attention as Munetaka Murakami or Tatsuya Imai, who are both expected to land larger deals when/if they end up signing with a big league club. Just a few days back, it didn’t even look like Okamoto was going to be making the transition from NPB to MLB, as a report from Francys Romero had dampened expectations, which wasn’t a major surprise considering the Yomiuri Giants had NEVER posted a positional player before. That would’ve been a major blow for Okamoto, who doesn’t have the same amount of time as Murakami or Imai, as he enters his age-30 season in 2026.

For those not familiar with Okamoto, he bats from the right side and is known as one of the most consistent power bats in Japan (3x HR Champ). From 2018-2023, he hit at least 30 homers every season and even topped out at 41. Despite missing a good chunk of 2025 with an elbow injury after a collision at first base, he still managed to hit 15 homers in 69 games, which shows that he hasn’t lost his power stroke. Okamoto also plays both infield corners and has appeared in the outfield, with him being viewed as an above-average defender at first base, which should make Breslow’s ears perk up after he cited improved defense as one of his biggest focuses this winter.

Across 11 seasons with the Giants, Okamoto has slashed .277/.361/.521/.886 with 248 long balls, 212 doubles, and 717 RBI in 1,074 games. Some of my favorite parts of Okamoto’s profile go beyond the typical slash line or home run total though. He posted the lowest K% of his career in 2025, with it coming in at 11.3. That sounds refreshing on a Red Sox roster that had the 10th-highest K% in MLB last season and the most strikeouts of any team with RISP. Not to mention, his BB% was the exact same mark, so he should be able to post some really strong OBP numbers, which gives his overall offensive profile a really solid floor.

Beyond that, we’ve heard Sam Kennedy (310 To Left) continue to emphasize this philosophy of targeting players that fit Fenway Park. Hunter Renfroe and Tyler O’Neill are recent examples that came to Boston and immediately found a connection with the Green Monster thanks to their pull power. Okamoto lifts the ball to left field a ton, with 12 of his 15 homers going to left or left-center in 2025. Combining that with the highest AIR% in NPB since 2021 at 67.3 (minimum 1600 PA), that feels like a pretty damn good match. If you lift the ball a lot at Fenway Park to left field, you’re bound to pepper Landsowne, which is something this Red Sox team badly needs after ranking 23rd in homers after the Devers trade.

It’ll be interesting to see where Okamoto’s homer total lands against better pitching, but I fully expect him to be in the 20-25 range. His Average Exit Velocity in Japan was 3.1 MPH above the MLB average, but his Max Exit Velocity numbers were 2.4 MPH below. There’s bound to be some adjustments made once he starts working with a different coaching staff, but his ability to consistently make contact in the zone and lift the ball should breed really solid results, especially if he’s in a ballpark that’s built for him.

The common question for many hitters coming to MLB is how they perform against velocity, especially with it continuing to tick up each year. In NPB, the average fastball velocity is at 91.4, with the MLB being 3 ticks higher at 94.4. Shoutout to Yakyu Cosmopolitan for this great nugget (along with a bunch of other info in this article), but Okamoto has batted .298 (90-for-302) with 20 HR against fastballs at 93 or harder in his career. There’s also this clip of him flipping a Roki Sasaki 99 MPH to right-center in spring training a few years back.

Even with it being a shorter season for Okamoto in 2025, it’s hard to ignore a guy who ranked in the 100th percentile for OPS+ (minimum 200 PA), 91st percentile in K% and BB%, 74th percentile in Defensive Value, and 88th percentile in terms of range. There’s a bunch of similarities in his batted ball data to Seiya Suzuki as well, who I badly wanted in Boston a few years back. Suzuki just finished his 3rd straight season with a 130 OPS+, and if Okamoto is only in the 115-120 range, that should still be a really good big league player, especially if his defensive reputation carries over.

Going back to the 2023 World Baseball Classic, Okamoto performed well for Team Japan, as he slashed .333/.556/.7222/1.278 and smoked 2 homers. That was the 2nd-best OPS on the roster, only trailing Shohei Ohtani (minimum 7 games). He even took Kyle Freeland deep in the Championship Game with a 407 FT bomb over the left-center wall, which ended up being the winning run for Team Japan.

I understand the hype behind Murakami when looking at his power potential, but a 29.5 and 28.6 K% over the last two seasons worries me greatly, especially when facing lesser stuff on a regular basis. We saw both Suzuki and Yoshida have their K% increase after coming to MLB. Add in the struggles against velocity and a lukewarm defensive profile and it doesn’t do much for me. Marc Feinsand of MLB.com recently reported that the Red Sox could be one of the teams in on Murakami depending on his ability to handle first and third or be a DH, but there hasn’t been any reporting beside that. Hopefully we see a more firm report around Okamoto in the coming weeks, especially since we all know he’s coming over now.

It’s hard to predict what Okamoto will be looking at in terms of offers. Seiya Suzuki got 5-years, $85 MM before the 2022 season, but he was 27 and offered more athleticism. We all remember Masataka Yoshida getting 5-years, $90 MM with him being framed as a left fielder, which was entering his age-29 season. Based on how first baseman have typically been viewed in recent years, I’m going to guess he gets a 4-year, $68 MM deal, but that doesn’t include the release fees, which can be found here.

If the Red Sox pursue Okamoto, they have a chance to cross off three boxes on their offseason checklist pretty quickly, and that’s more homers, improved defense, and the hole at first base. It also gives them a bit of leverage on the Bregman front, even though I badly want the Red Sox to bring him back. While I’m still a Triston Casas truther, I’d prefer if he could get some time at Triple-A to find himself again after a couple of extremely tough years.

This also takes you out of the Alonso market, which I understand is something that angers a lot of people. At the moment, he’s looking for a 7-year deal and I have ZERO interest going beyond 4 years on a higher AAV deal. Alonso is also a horrendous defender, which does you no favors after leading MLB in errors last season. Okamato feels like a strong middle-ground that also doesn’t stop you from pursuing Kyle Schwarber or throwing more money at a #2 starter, which should be a priority for this team.

It should be a fascinating offseason for the Red Sox, who seemingly have a number of options and the pathways they could go with their current needs. There’s no excuse for this roster not to be viewed as a World Series favorite going into spring training in 2026. Are those big expectations for Craig Breslow? 100%. But it doesn’t matter at this point, because you need to take advantage of the window that has opened up, especially when you have the type of assets this front office is working with. Get to cooking.