The Reds optioned Mey to Triple-A Louisville on Wednesday.
Mey will fall short of a spot in Cincinnati's Opening Day bullpen after surrendering nine earned runs in just six Cactus League innings. Although he struggled this spring, the 24-year-old righty posted a 3.43 ERA in 21 innings with the Reds last season and a 2.48 ERA across 40 frames in the minors, so he figures to rejoin the big-league squad at some point this year whenever Cincinnati needs a fresh arm.