Zerpa was called up from Double-A Northwest Arkansas on Monday.
Zerpa will serve as the Royals' 27th man for Monday's doubleheader against the Tigers. He's yet to pitch in the big leagues this season, but he's compiled a 4.36 ERA and 1.42 WHIP with 69 punchouts over 64 innings in 13 starts in Double-A this year. Zerpa will likely be returned to the minor leagues following Monday's contests.