The Royals will call up Zerpa from Triple-A Omaha on Thursday to start the team's series finale with Cleveland at Kauffman Stadium, Anne Rogers of MLB.com reports.
The 22-year-old lefty will be taking the rotation spot of Brady Singer (upper arm), who was placed on the 10-day injured list Wednesday. Zerpa began the season at High-A Quad Cities and submitted a 2.59 ERA and 0.97 WHIP in 41.2 innings, but he's faltered during his brief time in the upper levels of the minors. Between stops at Omaha and Double-A Northwest Arkansas, Zerpa has compiled a 6.36 ERA, 1.56 WHIP and a 55:20 K:BB across 46.2 frames.