The Padres optioned Hart to Triple-A El Paso on Tuesday.
The left-hander was unable to earn rotation spot to begin the season after a solid showing during spring training, and he was inconsistent as a reliever with a 5.40 ERA, 1.08 WHIP and 10:6 K:BB over 16.2 innings. Yuki Matsui (groin) was reinstated from the injured list to take Hart's roster spot.