Jhonathan Díaz: Everything you need to know

Diaz was added to the Mariners' Spring Training roster as a non-roster invitee. Diaz was designated for assignment and outrighted to Triple-A in January, when the Mariners acquired Cooper Criswell. The left-hander will likely be a depth option in Seattle's bullpen this season. He made just one big-league appearance in 2025.

The Mariners outrighted Diaz to Triple-A Tacoma on Wednesday. Diaz was removed from the Mariners' 40-man roster last week but will remain in the organization after passing through waivers unclaimed. The left-hander has collected a 4.66 ERA and 33:27 K:BB over 46.1 frames covering parts of five seasons at the major-league level.

The Mariners designated Diaz for assignment Friday, Adam Jude of The Seattle Times reports. With Cooper Criswell coming over from the Mets in a trade, Diaz will give up his place on the Mariners' 40-man roster. The 29-year-old southpaw made just one appearance with the Mariners near the start of the 2025 regular season, during which he gave up one hit and struck out one batter over 1.1 innings. He spent the rest of the season at Triple-A Tacoma and turned in a 4.15 ERA and 1.32 WHIP across 138.2 frames.