The Mariners announced Friday that they’ve recalled top pitching prospect Justus Sheffield for his team debut and designated righty Shawn Armstrong for assignment. Sheffield’s promotion is expected to be a short-term one, per Ryan Divish of the Seattle Times, who tweets that the lefty is expected to be optioned back to Triple-A Tacoma after tonight’s game. At that point, newly acquired Mike Wright will be added to the MLB roster in his place.
Sheffield, 22, has been regarded as one of the game’s top pitching prospects for the majority of his professional career. The Indians selected him with the 31st overall pick in the 2014 draft but later traded him to the Yankees alongside Clint Frazier in the trade that netted them Andrew Miller. Sheffield made his big league debut with the Yankees last September but tossed just 2 2/3 innings of relief. The Yankees flipped him to the Mariners this winter as the centerpiece of the James Paxton trade.
Per MLB.com’s Greg Johns, Sheffield won’t actually start tonight’s game; rather, he’ll follow Yusei Kikuchi in relief. Kikuchi will function as an opener in tonight’s game, pitching only one inning as part of the Mariners’ plan to acclimate the Japanese rookie to a larger workload (both in terms of volume of innings and the frequency with which he pitches as compared to Japan’s Nippon Professional Baseball, where starters pitch every sixth day). At some point, of course, the Mariners will take a look at Sheffield as a full-time rotation cog, though that apparently won’t come until later in the season. For now, righty Erik Swanson (also acquired from the Yankees in the Paxton swap) is getting the first look in the rotation.
The Mariners will now have a week to trade Armstrong or pass him through outright waivers. The organization likely hopes to be able to retain the 28-year-old, who was brilliant in 56 innings of Triple-A ball last season (1.77 ERA, 13.2 K/9) before posting a 1.23 ERA and a 15-to-3 K/BB ratio in 14 2/3 innings at the big league level. Armstrong has been tagged for six runs on eight hits and three walks through just 3 2/3 innings with the Mariners so far in 2019. Armstrong is out of minor league options, so any club that acquires him would have to carry him on its active roster (or else once again try to pass him through outright waivers).