Mariners designate Zach Pop, select Juan Burgos

The Mariners announced that right-hander Zach Pop has been designated for assignment.  Juan Burgos’ contract has been selected from Triple-A in the corresponding move, and Burgos will be making his Major League debut whenever he appears in his first game.

Pop was signed to a minors contract in April, and he was selected to Seattle’s active roster just over two weeks ago.  The brief audition hasn’t gone well, as Pop has allowed three homers over just 5 1/3 innings pitched, resulting in a 13.50 ERA to show for his four appearances in a Mariners uniform.  Most of the damage came on Thursday, when Pop was charged with eight runs (seven earned) during a disastrous inning of work in the Twins’ 10-1 win over the Mariners.

That rough outing might close the book on Pop’s time in the Pacific Northwest.  He is out of minor league options, so the M’s had to designate him for assignment and expose the righty to waivers before attempting to move him to Triple-A and off the 40-man roster.

Another club could put in a claim, perhaps figuring that Pop was still a little rusty after dealing with some elbow inflammation near the end of his Spring Training stint with the Blue Jays.  That said, Pop has a 6.42 ERA in 67 1/3 MLB innings with Toronto and Seattle since the start of the 2023 season, as the excellent numbers the grounder specialist posted in 2022 fade further into memory. Opposing batters have gone yard 16 times on Pop in those 67 1/3 frames, translating to a 27.6% home run rate.

The 25-year-old Burgos was an international signing for the Mariners in 2019, and he has booked his ticket to the majors due to a sterling 0.62 ERA over 29 innings at the Double-A and Triple-A levels.  Much of that work has come at Double-A, as Burgos was only just promoted to Tacoma earlier this week, and he made all of one appearance with the Rainier before getting the call to the majors.

A .129 BABIP has contributed heavily to Burgos’ tiny ERA, but his 27.8% strikeout rate and 6.5% rate have been impressive.  The latter stat is notable since Burgos had some big control problems early in his career, yet his walk rates have steadily improved over time.  Burgos relies heavily (44.4% of the time this season) on his cutter, and his slider has averaged 95.9mph in 2025.  Even if he is up primarily as a fresh arm for Seattle’s pen this weekend, Burgos should get to officially mint himself as a big leaguer and get a chance to show what he can do for the Mariners’ coaching staff.