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Mariners Next Roster Move Could Define Their October

Originally posted on Athlon Sports | By Kristie Ackert | Last updated Oct 11, 2025 8:14 PM ET

Highlights

Bryan Woo could rejoin the Mariners during the ALCS after missing the ALDS.
Jerry DiPoto expects Woo back by the middle of the series.
Dan Wilson said the team is still evaluating Woo’s readiness.

The Seattle Mariners’ biggest opponent right now isn’t the Toronto Blue Jays heading into the American League Championship Series.

It’s fatigue.

After grinding through a 15-inning clincher to reach the ALCS, Seattle now has to reassemble a pitching staff that can last another round. Every roster conversation starts with Bryan Woo.

Woo was left off the ALDS roster because of pectoral tightness but has been throwing bullpen sessions and trending in the right direction. Dan Wilson told reporters in Toronto for Saturday’s pre-series availability that the team is “continuing to assess” Woo’s progress.

“Yesterday’s bullpen went well,” Wilson said. “We’ll see how he bounces back. Then getting a chance to stretch it out a little bit more in the next few days will give us a really good indication of where he’s at.”

GM Jerry DiPoto was more definitive, telling reporters he expects Woo to be available by the middle of the series. That timeline would put him in play by Game 3 or 4 if he recovers smoothly.

Woo, 25, gave Seattle frontline production before the injury.

He went 15–7 with a 2.94 ERA, 198 strikeouts, and a 0.99 WHIP across 186 ⅔ innings this season. According to FanGraphs, he posted 4.4 WAR and finished among the league’s best in strikeout-to-walk rate. Baseball Savant data shows Woo in the 82nd percentile in strikeout rate and 84th percentile in limiting walks, with hitters batting just .210 off his fastball.

If he returns, Woo not only gives Seattle stability but a power arm capable of absorbing innings or bridging multiple relief spots when the bullpen runs thin.

He also brings credibility and leadership in the clubhouse.

Seattle Mariners pitcher Bryan Woo delivers a pitch against the Houston Astros.Erik Williams-Imagn Images

Roster Pressure

The 15-inning finale against Detroit taxed every arm on the roster. George Kirby, Logan Gilbert, and Luis Castillo were all pressed into high-leverage work. Over five games, Seattle used seven relievers and stretched matchups deep into the bullpen.

That kind of load leaves scars, even for a staff that led the American League in ERA (3.39) and strikeout-to-walk ratio (3.45) during the regular season. It also leaves little room for error in how the Mariners construct their ALCS roster.

Bryce Miller is lined up for Game 1, followed by Gilbert, Castillo, and Kirby. If Woo can’t go early, Emerson Hancock could serve as insurance or long relief. The bullpen core remains intact with Andrés Muñoz, Matt Brash, Gabe Speier, and Eduard Bazardo available, but the Mariners may need to swap in a fresh pitcher to weather the early innings of the series.

Wilson didn’t rule that out. “We’re certainly talking about that,” he said. “Using a lot of guys last night, we have to approach it a little differently this time around.”

The Woo Decision

Seattle has a few options, but each one comes with a cost.

If Woo is activated immediately, they’ll gain rotation flexibility but lose a reliever slot. If he’s held back, the bullpen could be overloaded in the first two games. There’s also the question of whether Woo’s role should be as a starter or a multi-inning bridge—a move that would allow Scott Servais to manage matchups more aggressively early in the series.

It’s not just about one arm. It’s about leverage, sequencing, and rest.

The Mariners’ style this season has been built on balance—timely pitching changes and maximizing short rest from their power arms. But the ALCS schedule is relentless. Seattle can’t afford to go thin. Every game will likely turn in the sixth or seventh inning, where fresh arms can make or break a lead.

What Comes Next

Woo’s return could stabilize everything. His presence allows the rest of the rotation to stay aligned, the bullpen to reset, and the team to manage from strength instead of exhaustion.

Wilson’s cautious tone suggests the Mariners won’t rush him. DiPoto’s optimism hints at urgency. The final roster will show whose philosophy wins out.

Seattle doesn’t need to reinvent its formula to reach the World Series—it just needs enough arms to keep the plan alive.

If Woo can give them that by the middle of the series, the Mariners’ biggest weakness turns back into their strength.

This article first appeared on Athlon Sports and was syndicated with permission.

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