Height: 6'0" Weight: 180
Bats/Throws: Right / Right
Born: 06/06/1995 in Houston, Texas
College: Stephen F. Austin State University
Acquired: Selected in the Rule 5 draft from the Detroit Tigers (12/10/2020)
Salary: Not available
MLB Debut: 04/01/2021
Free Agent after: season
Twitter handle: @willyvest
This hard-throwing Texan may or may not be on the roster for Your Seattle Mariners this Opening Day, but if he isn't, he'll have been sent packing. That's because, like Yohan Ramírez and Brandon Brennan before him, Vest came to the M's via the Rule 5 draft and therefore must be on the Major League roster for the entirety of the 2021 season or be offered back to his prior team, in this case the Detroit Tigers. Unfortunately for the M's, Vest's spring training hasn't been all that great; the decision of whether or not to hang onto him would be easy if the big right-hander had turned in a solid showing in the Cactus League, but as instead, Vest has pitched to a 6.50 ERA and a near-1.500 WHIP at the time of this writing. There's a lot of promise here—Vest throws three quality pitches and according to manager Scott Servais "made a very strong first impression" at spring camp—but the fact of the matter is, as a Rule 5 guy he has to be able to get big-league batters out on the regular, and that's been a problem so far. Still, the M's may not want to let him go back to Detroit and thus risk giving him one of the eight(!) relief slots in this year's bullpen.
Vest hasn't had much of a minor-league career yet, having been drafted out of college in 2017; after a nice pro debut in the short-season New York-Penn league, he struggled a bit at the Class-A levels in 2018, then dazzled in the High-A Florida State league in ’19 to earn quick promotion to Double-A Erie, where he was a lot less dazzling. He did fine in a very brief Triple-A callup, but the sample size (62⁄3 innings) is rather minuscule. He only converted to pitcher the same year he was drafted as one out of Stephen F. Austin University, having failed to hit as a shortstop. He tore his UCL on a throw to first in 2015 and needed Tommy John surgery, then after rehabbing for all of 2016 gave up being a position player and took the mound. From TJ-rehabbing shortstop to big-league relief pitcher in four years, that's his goal. It remains to be seen if he can pull it off.