Mariners Preview: Bullpen
Assuming good health, Seattle's bullpen is primed for success.
The final segment of our Mariners preview series aptly covers the relievers expected to preserve victories once manager Dan Wilson replaces his starter.
As we discussed in November, last year’s bullpen was not as dynamic as the 2024 edition. Nevertheless, the crew did an admirable job considering the added workload a banged-up rotation placed on it. In 2025, Seattle relievers covered 90 extra innings and 441 more hitters than the season prior.
The bullpen boasted a variety of valuable arms. Six had a better Expected Weighted On-base Average (xwOBA) than the MLB average. As we noted in our rotation preview, xwOBA is a Statcast product determined by quality of contact allowed. Unlike ERA, good or bad defense doesn’t influence xwOBA.
Better-Than-Average xwOBA in 2025*
Gabe Speier (.247)
Andrés Muñoz (.263)
Matt Brash (.282)
Eduard Bazardo (.285)
Carlos Vargas (.299)
Casey Legumina (.305)
* 150 batter minimum
Notable departures: Caleb Ferguson, Luke Jackson, Collin Snider, Tayler Saucedo, Gregory Santos, Trent Thornton
Looking ahead
Even though several recognizable relievers are no longer Mariners, many familiar faces from last year’s club remain. The first eight names listed below will probably be part of the Opening Day bullpen.
Reliever pool (2025 xwOBA)
Andrés Muñoz (.263)
Gabe Speier (.247)
Matt Brash (.282)
Eduard Bazardo (.285)
Carlos Vargas (.299)
Jose A. Ferrer (.294)
Casey Legumina (.305)
Cooper Criswell (MiLB)
Josh Simpson (.333)
Troy Taylor (MiLB)
Robinson Ortiz (MiLB)
Alex Hoppe (MiLB)
Ryan Loutos (MiLB)
Cole Wilcox (MiLB)
Domingo Gonzalez (MiLB)
Yosver Zulueta (MiLB)
Austin Kitchen (MiLB)+
Peyton Alford ( )+
Guillo Zuñiga ()+
Michael Rucker (DNP)+
Nick Davila (MiLB)+
Tyler Cleveland (MiLB)+
Charlie Beilenson (MiLB)+
+ Not on 40-man roster
Andrés Muñoz continued to be a premium closer. Once again, Muñoz had a double-digit walk rate. But he allowed just two home runs and boasted a .222 SLG that was second-lowest among 444 pitchers facing at least 150 hitters. An outstanding 32.7-percent strikeout rate certainly helped, too.
After a difficult 2024, Gabe Speier had a breakout campaign. Only Josh Hader, Aroldis Chapman, Brandon Woodruff, and Edwin Díaz produced a better xwOBA than Speier. It should be noted his career-high 33.7-percent strikeout rate led all Mariners and was 13th best among relievers.
Getting Matt Brash back from Tommy John surgery was a big boost. Brash’s strikeout rate was five points lower than his pre-surgery 34.4-percent. Still, Brash held opponents to a 13th-best 30.8-percent hard-hit rate.
The final 2025 appearance by Eduard Bazardo is a bad memory for Mariners fans. But big picture; he was a revelation for the team. Last year, Bazardo increased his sinker usage from 18.8-percent two seasons ago to 40.2-percent, which certainly paid off.
Last season, 124 pitchers threw at least 300 sinkers. Only Chapman (.150) had a lower wOBA with his sinker than Bazardo did (.199). On top of that, Bazardo’s sweeper, which he threw 42.8-percent of the time, limited opposing hitters to a superb .217 wOBA.
Opponents had a .273 AVG and .421 SLG against Carlos Vargas in 2025. These numbers are intriguing since just four pitchers had a lower barrel rate than Vargas (4.9-percent). Moreover, his 35.7-percent hard-hit rate ranked 19th, right behind Cy Young winner Chris Sale.
Not only did Vargas minimize damaging contact, he excelled at keeping the ball on the ground. His 57.1-percent ground ball rate was ninth best among 192 pitchers allowing 200 batted balls. This sounds great, but there’s a catch and it’s not a good one.
Opponents had a .317 AVG on ground balls hit off Vargas, which was 12th highest. For added context: Twenty-six pitchers had a ground ball rate over 50-percent, the right-hander was the only one with an AVG north of .300.
Vargas wasn’t the only Seattle pitcher with a suboptimal AVG on ground balls. It turns out the bullpen’s .286 AVG was the worst in baseball. Six Mariners, including starters Logan Gilbert and George Kirby, were higher than the MLB average.
M’s with High AVG on Ground Balls (50 GB min)
Casey Legumina (.358)
Gabe Speier (.345)
Carlos Vargas (.317)
Logan Gilbert (.283)
George Kirby (.269)
Matt Brash (.266)
MLB AVG on Ground Balls = .249
Some of you may point out Speier and Casey Legumina were ahead of Vargas on the preceding list. True. But he allowed 30 more grounders than Speier and Legumina combined. In the end, Vargas had the inauspicious distinction of leading MLB relievers with 44 ground ball hits.
The lack of ground ball success experienced by Vargas and others is probably attributable to the team’s infield defense being rated one of the least valuable in MLB. This will need to improve in 2026 considering the key relief arm the Mariners acquired in the offseason.
Jose A. Ferrer had the second highest ground ball rate. In December, we went into detail about Washington’s inferior defense and how the southpaw performed much better away from Nationals Park. His former home venue was the second-friendliest venue for hitting singles behind Coors Field.
We discussed Cooper Criswell as a possible replacement for the injured Bryce Miller in our rotation preview. Since he has zero minor-league options remaining, I suspect Criswell makes the team as a starter or long reliever. Legumina and several other relievers are in the same bucket as Criswell.
Minor-League Options of RP’s on 40-man Roster
Andrés Muñoz (n/a)
Matt Brash (2)
Jose A. Ferrer (2)
Eduard Bazardo (0)
Gabe Speier (0)
Carlos Vargas (0)
Casey Legumina (0)
Cooper Criswell (0)
Robinson Ortiz (3)
Troy Taylor (2)
Alex Hoppe (3)
Ryan Loutos (1)
Yosver Zulueta (1)
Cole Wilcox (3)
Domingo Gonzalez (2)
Josh Simpson (1)
Since the team used 33 pitchers last season, it’s reasonable to expect that more than a few of the minor-leaguers listed above will see time with the Mariners in 2026.
Outlook
Obviously, health can quickly derail a reliever’s season at any moment. But injuries aside, the Mariners have a formidable bullpen. The core of Muñoz, Speier, Brash, Ferrer, Bazardo, and Vargas should be capable of holding leads and saving wins all the way to the World Series.
And that’s without the benefit of the in-season additions, minor-league call-ups, and deadline deals the team will inevitably make.
My Oh My…