Seattle Mariners’ Stunning Surge: What’s Behind Their Unbelievable 15-Game Winning Streak and Playoff Breakthrough?

Wow, what a turnaround for the Seattle Mariners! After steamrolling through 15 of their last 16 contests, they’ve punched their ticket to the playoffs for only the second time since 2001 — and believe me, this isn’t just any postseason appearance. Tuesday’s nail-biter against the Colorado Rockies, sealed by Josh Naylor’s electrifying bases-clearing double, lit up T-Mobile Park and sealed the deal, especially when combined with the Yankees quietly clinching earlier that night. The Mariners are riding a surge that has them eyeing the AL West crown, a prize that has eluded them for nearly a quarter-century. Thanks to a recent sweep against the formidable Houston Astros, Seattle not only holds the tiebreaker but seems poised to wrestle control away from a dynasty that’s dominated their division play for years. With a magic number tantalizingly low and a potent mix of sluggers and pitchers firing on all cylinders, the Mariners are not just in the dance — they’re taking the lead. The October stage awaits, and this Seattle squad looks ready to surprise more than a few skeptics along the way.

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The Seattle Mariners have won 15 of their last 16 games and have now clinched a playoff berth for the second time since 2001.

The Mariners earned a spot in this year’s postseason Tuesday night with a 4-3 win over the Colorado Rockies and a New York Yankees victory over the Chicago White Sox earlier in the night. Their win was a thriller, with Josh Naylor hitting a bases-clearing double in the eighth inning to electrify T-Mobile Park.

An AL West title, which has escaped the Mariners for 24 years, is in earshot. Thanks to a three-game series sweep of the Houston Astros over the weekend, Seattle owns the tiebreaker over the team that’s won their division each of the past seven 162-game seasons.

During the Astros’ streak of eight straight playoff appearances, they’ve reached the World Series four times and won it all twice. They’re now at risk of missing out on the playoffs for the first time since 2016. The Mariners, on the other hand, are already in — and they’re in control of their division dreams.

Their magic number is two, and could be down to one if the Astros lose Tuesday..

Not only is the AL West within reach, but so is the AL’s No. 2 seed, which would give the Mariners a bye in the wild-card round and home-field advantage for the AL Division Series. A sweep of the lowly Rockies and at least one loss by the Detroit Tigers in their series against the Cleveland Guardians would do the trick.

Seattle last made the playoffs in 2022, when it finished second in the AL West with a 90-72 record. Although the Mariners played October baseball that year, they had to start each of their two series on the road as the AL’s second wild-card team. The Mariners got past the Toronto Blue Jays before being swept by who else but the Astros in the ALDS.

The Mariners’ storybook 2025 season has featured a switch-hitting protagonist: catcher Cal Raleigh has turned into a home-run mashing sensation. He’s in striking distance of MLB’s 10th 60-homer season. He needs four dingers to tie Aaron Judge’s AL record of 62 that the Yankees star set in 2022.

Raleigh’s got a strong supporting cast, too.

Like Raleigh, three-time All-Star center fielder Julio Rodríguez came into Tuesday ranked top 10 in the majors in WAR. Entering this week’s series against the Rockies, left fielder Randy Arozarena, also an All-Star this season, was the third player on the Mariners with at least 27 homers in 2025, looking up at only Rodríguez and Raleigh on the team leaderboard in that department.

Seattle’s other two All-Stars this season are on its pitching staff: starter Bryan Woo and closer Andrés Muñoz. Woo has posted a 2.94 ERA, and Muñoz began the Rockies series third in the majors with 37 saves.

After a concerning end to August, Seattle has looked every bit the part of a contender in September.

Now the Mariners will officially be playing in October.