The Pirates optioned Mears to minor-league camp Tuesday.
The hard-throwing righty registered a 4.50 ERA in six spring games covering six innings. Mears also walked five batters and hit another, so he will work on his control with Triple-A Indianapolis. The 24-year-old debuted in the majors last summer, compiling a 5.40 ERA with a 7:7 BB:K in five innings.