Seattle Mariners Continuing AL West Postseason Dominance

The Houston Astros are doing a lot of heavy lifting in this set of years, making four World Series appearances since 2017, collecting a pair of titles along the way. The Rangers added a championship in 2023, taking down the Arizona Diamondbacks in five games.

Since 2010, the West has the most World Series appearances (and titles), making it seven times in 15 seasons (not including 2025 at this point), and has won the World Series three times. The winning teams were the Astros in 2022 and 2017, plus the Rangers' 2023 campaign. Houston also made it and lost in 2019 and 2021, while the Rangers made it and lost in 2010 and 2011.

If the Mariners win two more in the ALCS, it will be their first World Series appearance in franchise history, which dates back to 1977. What's happening right now is a pretty big deal for Seattle fans.

The AL East has made four World Series appearances, winning two—Boston in 2018 and 2013—while the AL Central has made it in four times and won once. For all of the coverage that the East gets, they have just as many Series appearances as the division with the White Sox, Royals, and Guardians. Kansas City still has more appearances than the New York Yankees in that span.

What About the A's?

The reason this is so fascinating, particularly when it comes to the Mariners this season, is that the Athletics played them about as close as you can play a club over the course of a season series. Seattle came out ahead, 7-6, but the A's actually outscored them, 49-48. The clubs were actually tied in the season series heading into their final matchup in 2025, which Seattle won, 11-4.

From the beginning of the campaign, the A's and Mariners series felt different. From 2021-2024, Seattle had absolutely dominated the A's, with the Mariners going 47-17 across those four seasons. While the Athletics were rebuilding during much of that time, the M's weren't necessarily a juggernaut themselves.

This season's matchups felt more like the A's and Angels matchups every year in the early 2000s. With just one Wild Card team at the time, and the Red Sox and Yankees in an arms race each season, there was a decent chance that only one of the A's or Angels would make the postseason in a given year, so those 19-20 games held more weight, and they were always back-and-forth affairs.

While the A's still finished at 76-86 this season, they were able to push Seattle to the brink and put up a pretty good fight against them in 2025. That could end up boding well for the A's as they build out their roster for the 2026 campaign.