The Mariners have agreed to a minor league contract with right-hander Guillo Zuñiga, per the team’s transaction log at MLB.com. The former Cardinals and Angels reliever had been with the Phillies on a minor league deal but was granted his release earlier in the week.
Zuñiga, 26, has pitched in the majors in each of the past two seasons, totaling 19 2/3 frames between St. Louis and Anaheim. He’s allowed 11 earned runs (5.03 ERA) on 16 hits and eight walks with a dozen strikeouts. The big 6’5″, 230-pound righty has posted similar numbers in Triple-A Lehigh Valley in 2025, logging a 5.14 ERA, a 23.5% strikeout rate and a 10.9% walk rate in 42 innings of relief.
While Zuñiga has yet to find much success in the majors or even in Triple-A, he still has plenty of appealing traits. He’s averaging 96.9 mph on his four-seamer this season in Triple-A and is sporting a 12.3% swinging-strike rate that’s north of the major league average. He’s not inducing enough chases off the plate, but opponents have made contact at a well below average 73.7% clip overall — including a weak 79.5% on pitches within the strike zone.
Opponents also had a hard time making high-impact contact against Zuñiga, evidenced by a tepid 87.7 mph average exit velocity and 32.5% hard-hit rate. This year’s 46.9% grounder rate is a strong mark that’s notably higher than his recent seasons in the upper minors, perhaps due to throwing fewer fastballs and ramping up the usage of his slider and changeup.
The Mariners already have a strong back end of the bullpen. Closer Andrés Muñoz (1.69 ERA) and setup men Matt Brash (1.86), Gabe Speier (2.39), Eduard Bazardo (2.65) and Carlos Vargas (3.66) have all posted strong run-prevention numbers on the season. The other few spots in the ’pen are a bit in flux, however. Caleb Ferguson has struggled since coming over from the Pirates at the trade deadline. Tayler Saucedo has given up 11 runs in 10 1/3 innings this season. Starter-turned-reliever Emerson Hancock and veteran Luke Jackson were added to the mix when rosters expanded Monday.
Zuñiga won’t necessarily get a look in the majors, but if he impresses in his first few looks over in Tacoma, it’s feasible that he could pitch his way into a big league audition. He didn’t sign with the Mariners until Sept. 2, so he won’t be postseason-eligible even if he does push his way to the big leagues, but he’s a hard-throwing 26-year-old with a minor league option remaining and six additional seasons of club control, so he’s a sensible enough flier — especially for a team with a long track record of converting bargain-bin relief pickups into quality members of the major league bullpen.