The Seattle Mariners announced Saturday that they have designated veteran RHP reliever Zach Pop for assignment. Correspondingly, they have selected the contract of RHP reliever Juan Burgos from the Triple-A Tacoma Rainiers and are promoting him to the big league bullpen ahead of this evening’s game against the Texas Rangers.

Pop had an unfortunate, brief saga with Seattle, working a couple of dutiful, scoreless multi-inning appearances and a third with a single run allowed on a solo shot in the hot, windy Chicago air. However, an absolute implosion in Minnesota was one of the worst relief appearances in recent memory by a M’s arm, allowing eight runs, seven of which were earned, on six hits and two walks, along with a pair of big flies, swelling a 2-0 deficit to 10-0 and leading Seattle to quickly allow Pop to sop up the runs in a suddenly unwinnable contest. He may clear waivers and return to Tacoma, though his groundball-heavy style may prove useful, despite dismal results in the bigs now for a few seasons running.

On the other side of things is Juan Burgos, a 25 year old righty out of the Dominican Republic who was signed in the 2019 international amateur free agent class. Burgos got off to a slow and rocky start, and having signed ahead of his age-19 season, he was already in a different stage than some of his contemporaries. Despite effectiveness, Burgos demonstrated deeply inconsistent command through his first few professional seasons, before settling in at last in 2023-24 as an older reliever for the Single-A levels. While he received a bump up to Double-A Arkansas at the start of 2025, Max wrote on Burgos a few weeks ago to highlight his unassuming trajectory:

He’s been lost in the shuffle a bit, but Juan Burgos has fully emerged as an interesting relief prospect for the Mariners. He’s been good for several years now, however it’s been another level this season. With a 0.90 ERA on the season and a fastball that’s been up to 98, Burgos isn’t a huge strikeout guy but uses his cutter and slider combo to induce soft contact. There’s some inherent boost he’s getting from pitching in Arkansas instead of Funko Field, however he’s performed this well with lower K and GB rates than his career norms. Assuming everything balances out, we could see a truly special season from the young right hander.

That ERA has only improved since then, with a recent promotion to Triple-A and a scoreless frame there, he’s now rocking a 0.62/2.57 ERA/FIP, with 30 strikeouts to just seven walks in 29.0 frames this season. As Kate mentioned in the roundup of several minor league promotions this past week, Burgos is one of a couple relievers Seattle clearly thinks are primetime ready or adjacent and want on hand ASAP.

If and when Burgos debuts, he will be the most recent international amateur pitcher signed and developed by the Mariners (a.k.a. not traded and returned Juan Then) to make it to the majors since August 14th of 2017, when Thyago Vieira of Brazil’s (in?)famous debut.

Congratulations to Juan, and per the Mariners graphic, welcome to the show.

Mariners PR