He spent another season and a half with the Indians, then was traded to the Kansas City Royals on June 8, 1973, for Mike Jackson; the Royals had been particularly interested in acquiring Mingori since he was a Kansas City native. Mingori had 36 appearances in both 1974 and 1975, and had ERAs of 2.81 and 2.50. He followed that up with a 5–5 record and 2.32 ERA in 55 appearances in 1976.
He spent another season and a half with the Indians, then was traded to the Kansas City Royals on June 8, 1973, for Mike Jackson; the Royals had been particularly interested in acquiring Mingori since he was a Kansas City native. Mingori had 36 appearances in both 1974 and 1975, and had ERAs of 2.81 and 2.50. He followed that up with a 5–5 record and 2.32 ERA in 55 appearances in 1976.