Yuki Matsui and the Foibles of Being Good in an Elite Bullpen

[Brandon Glick]

It's no secret that the San Diego Padres' best unit is the bullpen. An offense with big names but meager production and a rotation that may struggle to put warm bodies on the mound can hardly amount to the awe-inspiring awesomeness of a relief corps helmed by Mason Miller, Adrian Morejon, Jeremiah Estrada, and others.

That's true even when accounting for the losses of Robert Suarez in free agency and Jason Adam to injury. The Friars' bullpen ranked first in MLB in ERA (3.06) and saves (49) this past season while finishing top-three in strikeout rate (25.8%) and FIP (3.53). The group was dominant, and the same should be the case in 2026, so long as A.J. Preller doesn't get any bright ideas or blockbuster trade proposals.

Everyone's stats are impressive, and I don't need to inundate you with all of them here; Miller (2.23 FIP, 44.4% strikeout rate), Morejon (2.28 FIP, .147 wOBA allowed to left-handed batters), Estrada (3.55 FIP, team-leading 77 appearances), and Adam (3.07 FIP, 33.3% whiff rate) all thrived in their respective domains of expertise. So long as that quarter is healthy and still on the roster, they'll form the backbone of the Padres' high-leverage operation.

Even the team's next tier of relievers is a sturdy bunch — Wandy Peralta, David Morgan, and Bradgley Rodriguez all had strong results in 2025, and as middle-inning relievers, they can surely be counted on to bridge the gap between the... questionable starting rotation and the fantastic back-end of the bullpen. And none of this even accounts for the swingmen the team has signed in free agency this offseason (Kyle Hart, Ty Adcock, and Daison Acosta). There's impact, depth, and everything in between in this bullpen. Truly, the Padres should feel comfortable leaning hard on the unit in 2026.

That brings us to Yuki Matsui, who occupies a bizarre space as a good reliever in an elite bullpen. The 30-year-old southpaw has two years remaining (plus a player option) on the original five-year contract he signed back in 2023, and he's been aggressively average in his two years with the Padres. In 126 innings, he's logged a 3.86 ERA, 3.52 xERA, and 4.40 FIP in 126.0 innings, all totaling up to exactly 0.0 fWAR.

That's not a "bad" pitcher by any means, but among a crowd of thunderbolt-hurling closers and lefty-dominating southpaws, Matsui stands out only because he doesn't stand out. He was better in 2024 than he was this past season, but concerns about his size (5'8", 165 pounds when soaking wet) and lackluster velocity have proven valid against big-league competition. After striking out more than 33% of hitters in NPB from 2018-23, he's sitting at a 24.6% strikeout rate in MLB.

Again, there's nothing wrong with a low-leverage reliever who posts mid-3.00 ERAs and strikes out a quarter of the batters he faces. But Matsui was billed for so much more after shredding Japanese hitters to the tune of a 2.40 ERA with the Tohoku Rakuten Golden Eagles. He's still getting hitters to whiff and chase at above-average rates, but his failure to induce ground balls or limit free passes has earned him a demotion to the third-string lefty role out of the 'pen.

None of this means Matsui can't put together the caliber of season his overseas success once portended. His splitter (.249 xwOBA in 2025) remains an effective offering against right-handed batters, hence why he's held reverse splits with the Padres. His fastball (40% usage in MLB) remains problematic, though he's gotten enough production out of his slider and sweeper versus lefties to hold them relatively in check.

The primary issue is that he's got no vertical variance in his offerings — his slider, sweeper, and splitter all hover within a few inches of each other on the y-axis — other than his fastball, which is so dependent on induced rise that it tends to get hammered if it's not up in the zone. The reintroduction of his curveball or sinker might help matters, but as a one-inning reliever, developing a fifth or even sixth pitch isn't high on the list of priorities for Matsui; he needs to find the right balance of his current offerings to stand a better chance against MLB competition.

*Graphic courtesy of Baseball Savant

The real trap facing Matsui is what the preamble of this article discussed: opportunity. Barring injury, there's just not many visible paths for the left-hander to garner any type of meaningful innings for Craig Stammen in 2026. His reverse splits mean Peralta or Morejon will always get the preferential treatment against left-handed batters, and his lack of elite strikeout stuff will keep him from getting leverage spots with people on base.

I'd be remiss not to wrap this up with a final reminder that Yuki Matsui is a good pitcher. He'll never be as dominant as Mason Miller or Adrian Morejon, but neither will 99% of professional pitchers. They just represent a different class of hurler than Matsui does. There's no shame in that. But because those two — and all the other aforementioned elite relievers the Padres employ — occupy roles in the same bullpen as Matsui, the Japanese southpaw finds himself on the fringes of the roster this offseason.

Sometimes, simply being "good" isn't good enough.

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