As the trade deadline approached last season, the Seattle Mariners were in the mix for high-leverage relievers. They even thought they were going to get a deal done for perhaps the best arm in the market: flamethrowing Minnesota Twins closer Jhoan Duran.

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Multiple MLB insiders have since stated they also thought a trade that would send Duran to Seattle would happen.

Instead, the Twins went with an offer from the Phillies and sent their star closer to Philadelphia, and the Mariners lone bullpen add was lefty Caleb Ferguson.

At the time, it felt like a high-leverage arm was the missing piece from the Mariners’ trade deadline haul, which proved to be true as they fell one win shy of reaching the Fall Classic in part due to a taxed bullpen that relied on the same four arms for nearly all of its leverage spots.

As the M’s go through the offseason and prepare for 2026, the bullpen remains as an area to upgrade. It’s not an area they have spent high on in the past under president of baseball operations Jerry Dipoto, but that could change after the franchise was on the doorstep of its first World Series appearance.

If the Mariners are to invest in their bullpen this offseason, here are some of the top arms they could go after.

Ryan Helsley

A two-time All-Star, Helsley was one of the top relievers moved at this year’s trade deadline. From 2022-24, the 31-year-old right-hander was second among qualified relievers in fWAR (5.7), third in ERA (1.83) and eighth in strikeout rate (34.6%). He was having another strong year with St. Louis before he was traded to the Mets this season and struggled to the rest of the way, posting a 7.20 ERA in 20 innings with New York. He finished the year with a 4.50 ERA and 1.54 WHIP over 56 innings.

Helsley features a four-pitch mix with a four-seam fastball that averages 99.3 mph, a hard slider, curveball and cutter. He heavily relies on the fastball and slider, which he’s combined to throw more than 90% of the time in each of the past three seasons.

Devin Williams

Williams is another star reliever coming off a down year. The two-time All-Star led qualified bullpen arms with a 1.66 ERA and was third with a 39.5% strikeout rate from 2022-24 with Milwaukee before posting a career-worst 4.79 ERA with the Yankees in 2025. However, he was still 99th percentile with a 37.7% whiff rate, and his 2.68 FIP with New York suggests there was a little bad luck involved.

Williams features one of the game’s best changeups, which could add a wrinkle to a slider-heavy Mariners bullpen. The pitch has produced a whiff rate over 40% in five different seasons. He also throws a four-seam fastball that sits at 94 mph and a rarely used cutter.

Pete Fairbanks

Fairbanks hit the free agent market after Tampa Bay turned down his $11 million option for 2026, but it certainly wasn’t due to performance. The 31-year-old right-hander has quietly been one of baseball’s more effective relievers for the past few seasons, including posting a 2.83 ERA and 1.04 WHIP over 60 1/3 innings pitched this year.

Fairbanks throws a four-seam fastball that averages 97.3 mph to go with a slider, changeup and cutter. Both the slider and cutter produced a whiff rate over 30% in 2025.

Danny Coulombe

Coulombe was one of the several high-leverage arms that struggled after being moved at the trade deadline. After posting 1.16 ERA in 31 innings with the Twins, the 36-year-old lefty surrendered seven runs and walked nine in 12 innings for the Rangers before being shutdown with left shoulder fatigue in September.

However, Coulombe has been among the game’s best left-handed relievers when healthy the past few seasons. He’d also bring a different look to a bullpen that mostly features hard-throwers. Coulombe rarely throws above 90 mph and relies on his 85 mph cutter the most. He also features a sinker, four-seamer, sweeper and knuckle curve.

Luke Weaver

Weaver was briefly a Mariner in 2023 before establishing himself as a reliable bullpen option for the Yankees. A former starter, the right-hander has a 3.21 ERA, 0.97 WHIP and 29.5% strikeout rate in 148 2/3 innings over the past two seasons, including a 3.62 ERA and 1.02 WHIP over 64 2/3 innings this season.

The 32 year old features a four-pitch mix led by a fastball that sits at 95 mph and a devastating changeup. Batters hit just .129 and had a 43.9% whiff rate against the changeup this season. He also throws a cutter and slider.

Five more names to know: LHP Gregory Soto, RHP Phil Maton, RHP Shawn Armstrong, LHP Holby Milner, RHP Emilio Pagán.

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