3 mistakes that doomed the Mariners in 2025 (and can't happen again in 2026)

The year 2025 is nearly over, and Seattle Mariners fans have many reasons to be sorry to see it go. It was a year of untold highs, from Cal Raleigh's historic 60-homer campaign to the club's first division title in 24 years to the deepest playoff run in franchise history.

Mariners fans are nonetheless headed into 2026 wanting more, precisely because that playoff run fell short of the ultimate prize: a World Series appearance.

To give credit where it's due, the Mariners' loss to the Toronto Blue Jays in the ALCS was a case of running head-first into a buzz saw. The Blue Jays were the best team in the American League this year, and they deserved to win the World Series just as much as the Los Angeles Dodgers, if not more so.

There were nonetheless some self-owns that doomed the Mariners this year, especially once the season got into October. They're worth going over in detail, with the idea being to drive home just how much these mistakes can't happen again in 2026.

3 mistakes that doomed the Mariners in 2025 (and can't happen again in 2026)

1. Trusting Randy Arozarena in the leadoff spot

To be fair, nobody mastered the leadoff spot for the Mariners this year. Some of that was bad luck, as the team had to throw its plan for the No. 1 hole out when Victor Robles got hurt in April. Some of it was a case of a good idea producing bad results, such as when J.P. Crawford got an extended look in the leadoff spot and fumbled it with a .261 OBP in his last 35 starts at the top of the order.

The shift to Arozarena, though, is where things really went wrong. It happened after the Mariners had upgraded their lineup with Josh Naylor and Eugenio Suárez, and the motivations for the change were never clear. Arozarena had a good-not-great .351 OBP at the time, and his profile has always been that of a middle-of-the-order type: a power-first hitter with lots of swing and miss.

Rather than supercharge the lineup, the move pretty much broke Arozarena after his All-Star first half. These were his splits by the time Wilson finally moved him back down in the order midway through the ALCS:

• August: .680 OPS, 5 HR
• September: .596 OPS, 1 HR
• October: .536 OPS, 1 HR

The leadoff troubles didn't cost the Mariners too much in the regular season, but they did in the playoffs. There was a lack of cohesion to the lineup in the ALDS and ALCS, resulting in too much effort for too few runs. To wit, only six of the 20 homers the team hit in October was with at least one man on base.

As for how the Mariners might fix this problem in 2026, they'll have an easy solution at leadoff if they trade for Brendan Donovan. Otherwise, Naylor has the bat-to-ball skill and on-base acumen to excel as a table-setter ahead of Raleigh and Julio Rodríguez.

2. Wearing out Bryan Woo

Out of the club's five core starters, only Luis Castillo didn't spend time on the injured list this year. Yet it's hard to look at the injuries to George Kirby, Logan Gilbert and Bryce Miller and wonder if they could have been avoided. Kirby hurt his shoulder in spring training, while Gilbert and Miller first landed on the IL with arm injuries in April and May, respectively.

With Bryan Woo, on the other hand, the Mariners might be guilty of having asked for too much.

He entered this year with a career high of 121.2 innings in the majors, and he crossed that threshold on July 25. He ultimately pitched at least five innings in all 30 of his outings, until a pectoral injury ended his regular season at a career-high 186.2 innings.

Though Woo's injury didn't seem serious at first, it rendered him unable to start and indeed unable to pitch until Game 5 of the ALCS. The Mariners suffered from his absence atop their rotation, which followed a 3.97 ERA in the regular season with a 4.47 ERA in the playoffs.

Hindsight is 20-20 and all, but the Mariners really should have considered giving Woo extra rest in the second half of the season. He instead continued to work exclusively on four or five days of rest, even after the rotation was back to 100-percent health in August.

Especially after this year's deep playoff run, the Mariners will need to be more intentional about not burning out their starters in 2026. That certainly goes for Woo, and should also go for Kirby, Gilbert and Miller and even for Castillo, who just turned 33 on December 12.

3. The Eduard Bazardo decision

Don't worry. We're not going to make everyone watch the footage again. Nobody needs to be reminded of what it looked like when George Springer ended the Mariners' season in the seventh inning of Game 7 of the ALCS.

The "What if?" of it all is still palpable, however. As much as Springer's swing, that outcome was determined by Wilson's decision to turn to Eduard Bazardo instead of Andrés Muñoz, Matt Brash or even Gabe Speier. Beyond simply being a bad matchup, it was akin to a role reversal for Bazardo.

Though he was one of Wilson's preferred relievers, he just didn't see as much high-leverage action as the other three. Here's how many of their total matchups were in high-leverage spots:

• Andrés Muñoz: 66.1 percent
• Matt Brash: 51.8 percent
• Gabe Speier: 38.7 percent
• Eduard Bazardo: 23.0 percent

In other words, Wilson assigned the biggest at-bat of the season to the guy who was least qualified to handle it. It never did make sense, and you wonder from his difficulties explaining himself if even Wilson wasn't sure of why he went to Bazardo and not to one of the other three.

Hopefully, Wilson has learned his lesson. What would help even more is if yet another option emerges for high-leverage matchups, and the Mariners sure seem to think that newcomer lefty Jose A. Ferrer is that guy.