Hart made a team-high 11 appearances during spring play, managing a nifty 1.64 ERA and 0.91 WHIP over 11 innings.
For the first time in his career, the 26-year-old enters Opening Day with a full-time gig in hand. Hart has put together solid minor-league numbers since being drafted by the O's in 2013. The left-handed specialist features a nasty arsenal of breaking pitches that he delivers from a low arm angle, which should help him carve out a nice niche in the bullpen.