Key Mariners reliever could face lengthy absence

Mariners setup men Matt Brash and Gregory Santos were both shut down due to arm troubles, and while it appears there’s good news on one, the outlook on the other is ominous. 

Ryan Divish of the Seattle Times reports that Santos played catch Tuesday and is beginning a throwing progression, but Brash is potentially facing an “extensive” absence. There’s some concern that Brash’s entire 2024 season may be in jeopardy, per Divish.

An absence of even moderate length for Brash would be a critical blow for the Mariners, who acquired the hard-throwing righty in a heist of a trade with the Padres and have since watched him blossom into a top prospect and potentially elite reliever. Brash’s 3.06 ERA in 70 2/3 innings last season is an impressive mark on its own, but that number doesn’t appropriately highlight some off-the-charts secondary metrics and a sensational four-month finish to close out the 2023 season.

Even as Brash posted a pedestrian 4.28 ERA through the season’s first two months, he was striking out a staggering 39.8% of his opponents against a respectable 8.9% walk rate. Fielding-independent metrics like FIP (1.92) and SIERA (2.34) were far, far more bullish on his work than his more rudimentary ERA.

Those numbers indeed proved a portent for a breakout. From Memorial Day weekend through season’s end, Brash turned in a sensational 2.36 ERA. His strikeout rate in that time clocked in at 32.4% against a 9.7% walk rate. Brash averaged a blistering 98.2 mph on his heater, generated swinging strikes at a hefty 15.4% clip and induced chases off the plate at a 33.6% rate — all while keeping the ball on the ground at a solid 44.4% clip. He finished the season with four saves and another 24 holds. Skeptics may want to see him sustain that over a full season or two, but that overpowering stretch had all the characteristics of one of MLB’s best relievers.

Unfortunately, it seems Brash might not get the opportunity to prove he can sustain that breakout for some time. Neither the team nor the player himself has provided any specifics as to the nature of the arm injury with which he’s dealing. Brash downplayed the issue last week, telling Divish and others that he’s simply “banged up,” while GM Justin Hollander merely stated that the hope was for Brash to return to a throwing program sooner than later. The lack of any real detail on the injury seemed foreboding at the time.

If the 25-year-old Brash is indeed going to be sidelined for a substantial portion — or, far worse, the entirety — of the 2024 campaign, a strong Mariners bullpen will take an unequivocal hit. Seattle relievers were fourth in the Majors with a 3.48 ERA last season and led the big leagues with a 3.64 SIERA. Brash played a major part, as did the since-traded Justin Topa, who went to the Twins as part of the Jorge Polanco deal.

The surprise acquisition of Santos late in the offseason helped to compensate for Topa’s departure, but a major injury for Brash would be difficult to overcome. His production throughout the summer and down the stretch in 2023 simply isn’t the type of performance that can be readily replaced.

The Mariners would still have one of the game’s best relievers, Andres Munoz, closing out games. Santos would headline a setup corps also featuring Gabe Speier, Trent Thornton and Tayler Saucedo — all of whom posted solid numbers in 2023 but have minimal big league track records.

There’s also still at least one notable reliever in free agency (Ryne Stanek), and the Mariners have had perhaps more success than any team in MLB at converting unheralded waiver pickups and minor league signees into impact relievers in recent years. 

Flamethrower Carlos Vargas, acquired in the Eugenio Suarez trade, is one power-armed candidate for such a breakout in Seattle. None of that takes away from the magnitude of a notable Brash injury, and at this stage of the offseason, the options to make a move to counteract such a significant loss are limited.