MLB trends: Kazuma Okamoto's big-league adjustment, Jesús Luzardo's big problem and the Mariners' ugly defense

The arrow is pointing up for Okamoto though. Following a 13 for 69 (.188) start with two homers in his first 18 games, he's 19 for 62 (.307) with eight homers in his last 17 games. He's also cut his strikeout rate from 32.9% of plate appearances to a more acceptable 26.8% during that time. Okamoto recently swatted four homers in a three-game span against the Twins.

Murakami had trouble handling velocity early on. For Okamoto, it was breaking balls. During the first 18 games, he hit a solid .250 against breaking balls, but with zero power (.250 slugging percentage) and while missing with 37% of his swings. The league averages are a .358 slugging percentage and 32% whiff rate against breaking balls. Okamoto had a clear vulnerability.

Since those first 18 games, Okamoto has hit .333 with an .833 slugging percentage against fastballs, and he's whittled his whiff rate down to 28%. Three of his last eight homers have come against breaking balls. You can chalk Okamoto's improved performance up to moving further back in the batter's box. The adjustment coincides perfectly with those first 18 games.

One interesting thing about Kazuma Okamoto, who's been hitting the ball a lot better over the last week ... last weekend in Arizona, he moved six inches further back in the box, where he's remained since. pic.twitter.com/mRKzv3LQMB

— Mike Petriello (@mike_petriello) April 27, 2026

There are two schools of thought about where to stand in the batter's box. One is that the hitter should stand far back to give himself as much time as possible to make a swing decision. The second is that the hitter should move up to give the pitch less time to break. There is no right answer. What works for one player may not work for another, and for Okamoto, moving back in the box has worked.

The Blue Jays stormed to the World Series last year because they were seemingly impossible to strike out, yes, but they combined those contact skills with power. They slugged .471 as a team last October. The power hasn't shown up yet this year. Toronto ranks 23rd in homers and 15th in slugging percentage. Okamoto figuring things out will help immensely with that power outage.

Jesús Luzardo's issues with men on base

Jesús Luzardo

PHI • SP • #44

ERA5.09

WHIP1.28

IP40.2

BB9

K51

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Last offseason, the Phillies traded two prospects to the Marlins for Jesús Luzardo, who gave them a 3.92 ERA and 216 strikeouts in 183 ⅔ innings in 2025. That earned him some Cy Young votes and a five-year, $135 million contract extension in March. This year's 5.09 ERA is an eyesore, though Luzardo's underlying numbers (2.27 FIP and 3.16 xERA) are much more promising.

For the third straight season, Luzardo's biggest issue is that he's a much different pitcher with runners on base. Almost every pitcher is less effective with men on, but Luzardo takes it to the extreme. Here are his numbers this season:

League-wide, the average pitcher is about 33 OPS points worse with runners on base than with the bases empty. Luzardo has been 316 OPS points worse, and while it is still early in the season and thus a small sample, he was 227 OPS points worse with runners on last year, so a similar split. He also gives back more with his strikeout rate than the average pitcher with men on.

There are countless reasons a pitcher could be worse with runners on base than with the bases empty, and I wouldn't immediately chalk it up to him getting rattled. It could be mechanics (pitching from the windup vs. pitching from the stretch), tipping your pitches, pitch selection, all of that and more. Luzardo has dealt with this before and is trying to figure it out.

"All my throws in between starts are out of the stretch," Luzardo told MLB.com last month. "We continue to work at that. Obviously, that's something that is kind of biting me, so it's something that we've got to fix ASAP. It's not tipping, so it's got to be something else. Whether it's pitch usage, I don't know. I don't want to speculate. I kind of want to dive deeper into it."

Luzardo struck out 18 and allowed only two runs in 13 ⅓ innings in his last two starts, albeit against below-average offenses (Giants and Marlins). He can be very good even while struggling with men on base. This is a real issue, though, and something that limits his ceiling a bit. With men on, Luzardo's isn't nearly as effective, and it turns into big innings too often.

The Mariners giving back too much on defense

A trendy World Series pick coming into the season, the Mariners entered Tuesday with a sluggish 17-19 record and a plus-3 run differential. That run differential was good for fourth best in the mediocrity-ridden AL, but isn't actually good. The Mariners won six of seven recently and looked like they were on the right track. Then they got swept by the Royals this past weekend.

"We'll make the adjustments that we have to," manager Dan Wilson told the Seattle Times after the sweep. "Baseball is about consistency, and that's what we want to get to. Right now, it seems like we're going through some swings back and forth."

The Mariners have operated with about a league-average offense (101 OPS+) and a better-than-average pitching staff (108 OPS+), even after adjusting for pitcher-friendly T-Mobile Park. What they do not have -- or even close to it -- is an average defense. They're dead last among all teams in outs above average. Here's the OAA breakdown:

The Mariners also rank 26th with a .681 Defensive Efficiency, which is a fancy way of saying they turn 68.1% of batted balls into outs. The league average is 69.7%. Opponents have hit .272 on ground balls against the Mariners. The league average is .242. On fly balls, they hit .112 against the Mariners. The league average is .097. It's bad all the way around.

At plus-1 OAA, second baseman Cole Young is the only positive defender on Seattle's roster. Even Julio Rodríguez, who has rated as an elite defender his entire career (plus-36 OAA from 2022-25), is down at minus-3 OAA in the early going. Randy Arozarena and Luke Raley have never been especially strong defenders. With Julio slumping in the field, the outfield is a major weak spot.

Bad defense hurts in so many ways. It's more hits falling in and more rallies for your opponents. It's more pitches and more stress on your pitchers. It's more bullpen activity. Victor Robles is on a rehab assignment and will be back soon, and you have to figure Rodríguez will get it together in the field. Otherwise, there's not much defensive improvement coming. This is who the Mariners are.

For a team built more on run prevention than run creation, this defense is worrisome. I wouldn't go so far as to call it a fatal flaw, at least not yet, but it's a problem, for sure. The Mariners simply give away too many outs and extra bases, and unless they go outside the organization for help, there are very few ways for them to fix it.