The Padres recalled Hart from Triple-A El Paso on Monday.
Hart made the Padres' Opening Day roster but was sent down in early May after collecting a 5.40 ERA and 10:6 K:BB over 16.2 innings in his first 12 appearances. He struggled at hitter-friendly El Paso, as well, with a 7.36 ERA, and the lefty will be used in a low-leverage situations.