Wanted: Bullpen help
As with every offseason, expect an influx of new relievers joining the Mariners and a few familiar faces in the current bullpen pitching elsewhere in 2026.
We’ve recently discussed position player needs for the Mariners and the current state of the starting rotation. Now, let’s turn our attention to the bullpen - the most volatile segment of the roster in terms of turnover and performance.
Turnover: Before considering the stable of relievers the Mariners used in 2025, let’s reflect on the comings and goings of Seattle’s bullpen in recent seasons. Doing so may help shape expectations for the offseason.
Since the end of 2021, between six and seven Seattle relievers logged at least 30 innings with the team each season. Yet, no more than three of those pitchers would reach 30 frames as a Mariner the following year. Considering relievers amassing the most innings tend to provide the greatest value to a club, the changing of the guard has been substantial and consistent.
The following illustrates Mariner relievers reaching 30 innings with the 2021 campaign being the baseline. Names in bold duplicated the accomplishment the next season. Only Andrés Muñoz made the list four times.
There are a variety of reasons relievers didn’t log 30-plus frames in consecutive years. Several were traded. Kendall Graveman, Paul Sewald, Erik Swanson, Will Vest, Justin Topa, Anthony Misiewicz, and Rafael Montero fall into this category.
Injuries affected the availability of Casey Sadler, Penn Murfee, Matt Brash, and Gabe Speier. Sadler hasn’t pitched in MLB since 2021. Murfee missed the 2024 season before appearing with the White Sox this year. Fortunately, Speier rebounded with an excellent 2025, as did Brash.
Others were subsequently plagued by ineffectiveness. Several pitched for Class-AAA Tacoma or were let go by the organization. Recognizable names include Drew Steckenrider, Matt Festa, Diego Castillo, and Tayler Saucedo.
When we focus on the 2025 bullpen, there has already been churn. Free agents Luke Jackson and Caleb Ferguson are no longer Mariners. Assuming neither re-signs, new acquisitions or someone from within will need to cover the 33.1 innings pitched by the duo.
Since we’re talking business, there’s another factor to consider - arbitration. Per MLB Trade Rumors, six Seattle relievers are eligible with varying levels of pay hikes projected.
Arb-Eligible SEA Pitchers
Trent Thornton ($2.5M)
Matt Brash ($1.8M)
Gabe Speier ($1.7M)
Tayler Saucedo ($1.1M)
Gregory Santos ($800K)
Jackson Kowar ($800K)
Source: MLB Trade Rumors
Relatively speaking, the preceding salaries don’t seem high to this blogger. Based on the quality of their performances in 2025, Matt Brash and Gabe Speier seem like no-brainers to return. That said, I have no idea on how the front office views the remaining names.
Would it make sense for the Mariners to obligate more money to Trent Thornton next year than Brash and Speier? Thornton’s numbers regressed in 2025 and the 32-year-old suffered a season-ending Achilles injury in August. To me, his future with the Mariners is unsettled.
The outlook for Tayler Saucedo also seems cloudy. Although his projected salary isn’t much higher than next year’s MLB minimum ($780,000), Saucedo made just 10 appearances with the Mariners this year due to ineffectiveness. The rest of the time, the southpaw pitched for Tacoma.
Jackson Kowar isn’t set for a big payday either. But the 29-year-old didn’t appear after August 18 due to a shoulder impingement. It’s worth noting Tommy John surgery cost Kowar all of last season and the first two months of the 2025 campaign.
Perhaps the most enigmatic figure is Gregory Santos. Since being acquired in February 2024, Santos has spent 315 days on the injured list with just 16 appearances as a Mariner. Being 26-years-old and possessing a promising arm are factors in his favor. Then again, spending time on the IL in each of the last four seasons isn’t.
Performance: The numbers tell us the 2024 bullpen was much better than this year’s version. It was top-5 in AVG, OBP, wOBA, xwOBA, plus strikeout and hard-hit rates. Pitching fewer innings than any relief staff in baseball certainly helped the cause.
This year’s crew ranked 11th in innings - commensurate with its overall effectiveness. Not terrible, but a noteworthy decline after a strong 2024.
Thoughts: Business-related attrition is a reason to reload. So is reversing the regression the bullpen experienced this year. Therefore, expect many new relievers with the Mariners by the times Spring Training begins. In fact, change is already underway.
Seattle has already acquired Cole Wilcox and Domingo González. The constant drumbeat of relief arms arriving via trades, waiver claims, and major- and minor-league free agent signings will continue between now and until forever.
Potential Relievers on 40-Man Roster (Nov 7, 2025)
Blas Castano
Cole Wilcox
Domingo González
Emerson Hancock
Carlos Vargas
Logan Evans
Casey Legumina
Gregory Santos
Matt Brash
Jackson Kowar
Troy Taylor
Trent Thornton
Andrés Muñoz
Eduard Bazardo
Jhonathan Díaz
Source: Baseball Reference
Just to be clear, I don’t know how the organization views Emerson Hancock, Logan Evans, Jhonathan Díaz, and Blas Castano. If I identified a potential starter pool, they would be on that list, too.
As the hot stove begins warming, we’ll revisit potential relief pitcher targets that might make sense for the Mariners to pursue. That said, I would be surprised if the team spent big on a high-profile free agent reliever. It doesn’t have a history of doing so. Plus, the organization is adept at guiding lesser-known pitchers towards becoming a better version of themselves.
Previous success stories include Graveman, Sewald, Swanson, Topa, Speier, and Brash. Granted, not every project delivered the superb results as these pitchers did. But the Mariners pitching lab clearly knows what it’s doing.
My Oh My…