Mariners claim RHP Jonathan Hernández off waivers from Texas; Gregory Santos to IL

RHP Brett de Geus designated for assignment

Looking to upgrade their bullpen at the deadline, the Rangers acquired RHP Andrew Chafin from Detroit. As a corresponding move, Texas DFA’d 28-year-old righty reliever Jonathan Hernández, who was claimed today off waivers by Seattle.

Hernández has been with the Rangers for his entire career, debuting with Texas in 2019. Hernández’s biggest issue has been with walks, as he’s run a double-digit walk rate each of the past three seasons. A sinker-slider pitcher who will occasionally mix in a changeup, Hernández’s slider has enormous swing-and-miss potential, running a near-40% Whiff rate. Hernández’s second-most-used pitch is his two-seamer, which has plus velocity, averaging almost 97 mph, but has been absolutely tattooed by big-league hitters this year as a result of poor location and running behind in counts. Hernández’s stuff is tantalizing, but it’s very hard to fix poor command at the big-league level; as a dart throw as a waiver claim, though, it’ll be interesting to see what he’s got, and if the vaunted Mariners pitching lab can get through to him in a way their AL West rival could not.

Here’s a clip where he strikes out three San Francisco Giants, one on each of his three pitches, so you can see what each looks like in action:

Warts and all, Hernández is a necessary acquisition, as the club announced today they are moving RHP Gregory Santos to the 15-day IL with right biceps inflammation. Santos will be sent to do biomechanical imaging, says GM Justin Hollander, to see if there’s a pervasive issue that’s causing this injury chain, but the good news is his MRI (not just on the biceps, but on his lat/shoulder area as well) came back clean. This is a developing situation and there’s no timetable yet on his return, but we’ll keep you updated.

In order to make room for Hernández on the roster, the Mariners designated RHP Brett de Geus for assignment. de Geus has been up and down a few times between Tacoma and the big-league club this year, and continues to struggle with his command despite having wipeout stuff. It’s hard to see another club adding him to their big-league roster with the inconsistencies he’s shown at Tacoma, but it is a pitching-desperate market out there; hopefully he’ll stay with the organization and continue to work towards harnessing his big stuff.