State of the Mariners – September 23rd, 2025
By Brittany Wisner, edited by Charles Hamaker
Seattle, WA - After falling in and out of the third American League wild card spot over the course of several weeks, the Seattle Mariners looked like a team teetering on the edge entering September, unclear whether they’d even make the postseason. They needed to catch fire fast if they wanted to control their October fate.
And catch fire they did.
Whether it was witchcraft, mustaches, or simply getting hot at just the right time, Seattle has gone on a scorching 14–1 run, vaulting to the top of the American League West and positioning themselves to claim their first division title since 2001.
The icing on the cake came in Houston this past weekend, in what was perhaps the most important regular-season series in recent franchise history. The path to the division was always going to run through the Astros – and not only did Seattle win the series, they were completely dominant in every facet. In the three-game series sweep, the Mariners never once trailed, thoroughly outpitching, outhitting, and outplaying the perennial AL West champs.
More than just a shift in standings and clinching of a critical tie-breaker, the series felt like an unofficial changing of the guard. The Mariners were completely overpowering, a sentiment echoed honestly within Houston’s clubhouse after game three.
“I think we did try our best,” Astros third baseman Carlos Correa told reporters after the game. “They were just better.”
“We didn’t have much to counter,” manager Joe Espada said.
The Mariners will hope to land the final punch this week by clinching their first division title in 24 years. Here’s how they can do it and how they’ve arrived at this pivotal point.
What Got Them Here
Starting Pitching
Seattle’s starting rotation– snake bitten by injuries for much of the season – is finally looking like they may be arriving at full strength.
Luis Castillo has rebounded after the toughest stretch he’s endured in a Mariner uniform. So far in September, “The Rock” has posted a 2.86 ERA in 22 innings pitched, limiting opponents to just two home runs and three walks, areas that have plagued him frequently this year.
Logan Gilbert has also shown glimpses of returning to form. The lanky right-hander has logged a 2.01 ERA in 22.1 innings in September, including two outings of six complete innings, an encouraging step as outing length had become a concern following his IL stint.
Logan Gilbert Average Innings Pitched per Game:
June - 5.0 innings
July - 5.1 innings
August - 5.2 innings
September - 5.4 innings
He was especially key in the pivotal rubber match against Houston, tossing six strong innings and allowing just one run on three hits. “Walter” also touched 97 mph with his 4-seamer several times, a level of velocity we haven’t seen him produce since his flexor strain in April.
George Kirby also saw an encouraging increase in velocity, touching 99 mph in Saturday’s matchup against Houston. Though command has been uncharacteristically inconsistent for Kirby this year, “Furious George” looked as sharp as ever, generating 11 whiffs from Astros’ batters and painting corners in high-stress moments that previously have gotten the best of him.
The Bullpen
In a similar vein, Seattle’s bullpen arms have produced their most clutch performances of the entire season. Collectively, they have posted a 2.99 ERA in the month of September, including allowing just one earned run during the Mariners’ undefeated 7-game homestand.
Eduard Bazardo, perhaps the unsung hero of this Mariners’ season, has been one of the best relievers in all of baseball this summer. He has not allowed an earned run since August 25th with opponents batting a measly .122 against him over that time. He has thrown more innings than any other Mariner reliever this year, nearly tripling his inning count from 2024. If and when Seattle makes the playoffs, Bazardo should be highlighted as a major contributor to the team’s success.
Offensive Explosion
Outside of a rare slump from Randy Arozarena, every qualified hitter in the Mariners’ lineup has a wRC+ above 100 in the month of September, according to Fangraphs:
Cal Raleigh - 192 wRC+
Jorge Polanco - 173 wRC+
Josh Naylor - 169 wRC+
J.P. Crawford - 154 wRC+
Julio Rodríguez - 151 wRC+
Eugenio Suárez - 107 wRC+
Their collective 132 wRC+ in the month of September is the best in baseball. They also have the second highest OPS (.826) and wOBA (.350) behind Philadelphia.
Learning From The Past
It’s no secret that the Mariners have failed to finish the job in recent years, missing the playoffs by a single game in 2023 and 2024. Those near-misses, while painful, may partially be fueling this season’s late surge.
Cal Raleigh thinks those experiences have reshaped how the team has approached this crucial stretch.
"This team has learned a lot over the past two years about finishing,” Raleigh told Seattle Sports’ Shannon Drayer. “You remember those struggles and it makes you focus and that much more energetic when you get to this time. You recognize what is important this time of the year."
That energy was on full display in Houston. Whether it was the uptick in velocity and intensity from the starting rotation or the relentless defensive efforts from Eugenio Suárez, Julio Rodríguez, and, most notably, Victor Robles, the Mariners looked like a team who thoroughly understood what was at stake–and played like it.
How They Can Clinch
There are several ways for Seattle to clinch both a playoff spot and the AL West title this week.
Their magic number to clinch a playoff berth sits at two. That can happen as early as tonight with a Mariner win and a New York Yankees defeat of the Chicago White Sox.
To clinch the division, the magic number is three and can happen as early as Wednesday. It will require any combination of three Mariners wins or Astros losses to cement their first division win in 24 years. Houston faces off against the Athletics – who have been playing better baseball as of late – for a three-game set.
Lastly, the recent collapse of the Detroit Tigers has opened the door for the Mariners to clinch a first-round bye if they can earn the 2nd seed in the playoffs. This can happen as early as Thursday if Seattle sweeps Colorado and the Tigers lose one of their games against a hot Cleveland Guardians team.
What’s Next?
Here’s how the final six games stack up for the Mariners as they return home to T-Mobile Park.
Seattle will open the homestand against the worst team in baseball, the Colorado Rockies (43-113), for three games that present the best opportunity for them to cement themselves in the postseason.
They’ll then close out the regular season with a three-game set against one of the best teams in baseball, the Los Angeles Dodgers (88–68). Ideally, Seattle will have already secured a playoff spot—or even the division—before the Dodgers arrive. But even if they haven’t, the matchup could still tilt in Seattle’s favor. With Los Angeles likely to have its postseason position locked in by the weekend, the Mariners may benefit from bullpen-heavy games as the Dodgers look to rest their starters, as well as possibly allowing their star hitters some time off their feet.
Lastly, this writer hopes every Mariner fan enjoys every second of this ride. You deserve it. Soak in every pitch, every trident raise, every heart-racing, high blood-pressure moment.
Go M’s.
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Check out our previous Seattle Mariners articles here.
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