Mariners sneak starter through waivers (but he's still on bottom of roster bubble)

The Seattle Mariners have been doing some roster tidying as spring training gets closer. That latest news is something of a surprise, at least to the extent that it means Jonathan Díaz is still with the team.

The left-hander was designated for assignment last week after the Mariners acquired Cooper Criswell, who figures to be the new long man in the bullpen for the 2026 season. On Wednesday, Seattle subsequently revealed that Díaz had been outrighted to Triple-A Tacoma.

This indicates that Díaz had cleared waivers. He's off the 40-man roster, but still part of the organization as a depth piece — though Darragh McDonald of MLB Trade Rumors notes that the southpaw has the right to elect free agency.

Mariners get to keep their starting depth intact with Jhonathan Díaz move

The positive read on this move is that it allows the Mariners to retain extra depth for their starting rotation. Which is good, because they should know after what they experienced in 2025 that they can't count on their starting five making every start in 2026.

At the outset of the winter, the shortage of options underneath Bryan Woo, Logan Gilbert, George Kirby, Luis Castillo and Bryce Miller was a relatively small, yet real concern. That is no longer really the case several months later. Emerson Hancock and Logan Evans are still there in reserve, and newcomers like Criswell, Dane Dunning and Randy Dobnak can also start in a pinch.

The same is also true of Díaz, who has made 20-plus starts for Tacoma in each of the last two seasons. The 29-year-old had one of his better seasons in 2025, making 26 starts and striking out 4.8 times as many batters as he walked over 138.2 innings.

When Díaz has been called upon in the majors, he's been used in relief more than as a starter. It would be a reach to say he's been an asset — he's made MLB appearances in five straight seasons, but in no more than five games in any of them — but nobody has ever seen flexibility as a bad thing.

As for what motivation Díaz has to stick with the Mariners in lieu of electing free agency, the choice was basically between a minor league assignment and a minor league contract with another team. He apparently preferred the familiarity of the Seattle organization.

Plus, there is the possibility of various World Baseball Classic assignments opening up more chances to pitch this spring. That could be good for Díaz and the other down-roster options the Mariners have on their pitching depth chart.