Atlanta recalled Hernandez from Triple-A Gwinnett on Monday.
He will serve as the 27th man for Monday's doubleheader against the Padres. Hernandez, 27, holds a 1.65 ERA and 22:9 K:BB across 16.1 innings this season at Gwinnett. He got into four games with Atlanta last season, allowing three runs in 3.2 frames.