Did the Mariners Just Make a Costly Mistake by Cutting Jhonathan Diaz?

There are always questions and debates following Monday's happenings, more so when Jhonathan Diaz was designated for assignment by the Seattle Mariners. Diaz, a crucial backup pitcher, was removed from the 40-man roster after Seattle acquired Casey Legumina from the Cincinnati Reds. The bottom line here is that there is a challenge in finding several starting pitchers after the top rotation, thus making it not know if this is the right decision or whether it is going to rebound the latter part.In a surprising roster adjustment, the Mariners traded for right-handed pitcher Casey Legumina from the Cincinnati Reds in exchange for cash considerations. As a corresponding move, they designated Jhonathan Diaz for assignment (DFA), leaving the 40-man roster full.The 28-year-old Diaz had been a reliable depth option for the team. In Triple-A Tacoma, he posted a 9-3 record with a 4.36 ERA across 23 appearances, proving himself as a dependable arm. Additionally, he was called up to the MLB squad multiple times in 2024, making five appearances (one start) and registering a 4.66 ERA.Now, the Mariners have five days to decide whether to trade, release, or outright Diaz to the minors. If another team claims him, Seattle could be left with even fewer backup options for its already thin pitching depth.While the Mariners boast one of the strongest starting rotations in baseball, their minor league depth is concerning. Beyond their top five starters, Emerson Hancock serves as the sixth option, and Diaz was their seventh. By removing him from the roster, they risk losing a solid backup without a clear replacement.Adding to the uncertainty, Diaz dominated in the Puerto Rican Winter League, going 4-0 with a 0.49 ERA in 36.2 innings. This level of performance suggests that he could still contribute at the major league level, making the Mariners' decision even more puzzling.While Legumina could prove to be a solid bullpen piece, the Mariners may have weakened their starting pitching depth at a critical time. If injuries strike the rotation, the lack of reliable arms in the system could come back to haunt them.Seattle fans will be watching closely to see if Diaz is picked up by another team—and whether this decision turns into one the Mariners regret.Also Read: PECOTA Projections Are Out, And the Chicago Cubs Are Making a Strong Comeback