Mariners’ momentum – After a sweep that pushed the Mariners into first place in the AL West, the Diamondbacks open this matchup with a different kind of question: can their offense keep catching fire while the pitching staff waits on injured starters to return around midseason?
The Mariners didn’t just win a series—they strung together a full roster performance. with every part of the lineup clicking at the same time. The result was a sweep that carried them into first place in the AL West after beating division-leading Athletics. It’s a payoff that feels bigger because the team is still not above .500—this West has been messy all year—but momentum in baseball has a way of turning “almost” into something sturdier.
For Arizona. this matchup arrives with its own kind of edge. built less on last week’s results and more on what’s still supposed to come back. The Diamondbacks entered the season in a difficult spot after failing to build off their surprise World Series run from 2023. even after investing money into their roster over the last few years. A key blow came through injuries: Corbin Burnes and a bunch of their best relievers went down. and the pitching staff wasn’t deep enough to cover the absences. That reality pushed a dramatic sell-off last summer, though Arizona managed to keep its core pieces intact.
That’s why the team has looked competitive this year. When two superstars are carrying the offense early in the season. it buys time—especially when injured pitchers are expected to return around midseason. The question hovering over Arizona now is whether the current version of the Diamondbacks can keep pace long enough for those reinforcements to matter.
Ketel Marte has been the clearest example of how the offense has answered the moment. Since May 9, Marte has collected 29 hits in 17 games, lifting his season wRC+ to 124. He struggled early in the season. and this surge looks like his results are catching up to what his peripherals have been signaling. Corbin Carroll has been steadier in a different way—he’s collected 22 hits over the same stretch. and it hasn’t felt like an outburst so much as more evidence that he’s been excellent all season.
There’s also a reminder that Arizona’s lineup doesn’t run on one storyline. Geraldo Perdomo’s breakout came last year, but he’s struggled in his follow-up season. His approach at the plate remains strong, even sharp, but the power that fueled the breakout has largely disappeared.
The Diamondbacks have added more internal urgency through recent promotions, and they come with notable roster swings. Ryan Waldschmidt has taken over in center field after Arizona designated Alek Thomas for assignment. Tommy Troy is now covering for the injured Lourdes Gurriel Jr.
Even with the movement, Arizona’s mix still stretches across age and experience. Nolan Arenado has played well in his first season with the Diamondbacks, producing his best offensive output since 2022. Ildemaro Vargas, at age 34, is also enjoying a breakout season.
On the pitching side, however, the instability is harder to sweep away. Zac Gallen suffered through the worst season of his career last year. With his final year of team control ending before free agency. the timing couldn’t have been worse—especially with a qualifying offer attached. He drew very little interest and wound up re-signing with Arizona in February. The early signs this year haven’t improved. Even at his peak, Gallen didn’t rely on overpowering stuff; he succeeded through a deep repertoire, command, and deception. Without much margin for error to begin with, his tricks have seemed to fail him over the past two years.
Ryne Nelson offers a different problem. He has a phenomenal fastball—nearly perfect backspin and enough carry at the top of the zone to make batters pop up or hit lazy fly balls when they can’t get under it. But it’s about all he’s got. His secondary pitches are average at best, and he leans far too heavily on his heater to get outs. His slider has shown a little promise, but he doesn’t use it enough to generate strikeouts. The bigger issue is the absence of a reliable weapon against left-handed batters; he previously dabbled with a changeup but it didn’t stick. Now he’s using a cutter to try to keep hitters off his four-seamer. but they’re crushing it once they see it.
Merrill Kelly’s season has carried its own disruptions. After being traded to the Rangers at the trade deadline last summer. he came back and re-signed with the Diamondbacks this offseason. But a nerve issue in his back sidelined him this spring, forcing him to ramp up on a delayed timeline. He missed the first three weeks of the season. When he returned. he struggled with command and feel—problems that matter because command and feel are essentially the only way he’s been successful throughout his career. He doesn’t overpower hitters. but he uses his deep repertoire to keep batters off balance when he hits his spots. His best pitch has been a hard changeup that dives off the table. along with a slider that’s getting a lot more use this year.
The Mariners’ winning run has mattered in the standings because it changed the tone of the whole division. Arizona’s urgency matters because their roster appears built for later—built for when the injured pitching pieces are ready around midseason. Between those two realities sits the real pressure of this series: one team is rolling with complete roster execution. and the other is trying to hold the line until its rotation can stop feeling patched together.
While that tension plays out, the rest of the AL West picture keeps shifting. The Athletics, after failing their test against the Mariners, now host the Yankees for three games this weekend. The Astros took three of four from the Rangers this week and swapped places with them in the standings. Houston—despite early season struggles—is now only 2.5 games back in the division thanks to a 7-3 record over their last 10 games. The Astros host the Brewers this weekend while the Rangers host the Royals.
Mariners vs Diamondbacks AL West standings Ketel Marte Corbin Carroll Zac Gallen Ryne Nelson Merrill Kelly Nolan Arenado Ryan Waldschmidt Tommy Troy Lourdes Gurriel Jr