Voth has some nasty stuff if he can harnass it
We start here by actually looking at what Voth can bring to the table for the Mariners. He brings four pitches to the table, and a decent usage on all of them. He's mainly a heater (44%), and then goes curve (29%), sweeper (16%), and cutter (11%).
He actually had bad luck on all of his pitches last year, with each of them sporting a higher BAA than the xBAA. The big one is the cutter, which had a .231 to .136 discrepancy.
His curveball stands out for the massive break that it has, sitting 6.1" above average and holding a dark red mark, showing it as one of the biggest breakers in baseball. It also boasts a massive RPM rate of 3,000+, also an elite mark. That isn't the only pitch with high RPMs, as his sweeper boasts the same thing. If the Mariners can work on his pitch selection and placement, the stuff will go from scary to straight-up nasty.
Back to the cutter, he had the expected BA against of .136, and an expected SLG of .224. It might be worth cutting massively back on the 4-seamer and leaning into the cutter. The stuff is there, and Voth is next up to see if the Mariners pitching lab can find success where others couldn't.