Oaks will join the Royals as their 26th man and start Game 1 of Saturday's doubleheader with the White Sox, Rustin Dodd of The Athletic Kansas City reports.
Oaks has a 3.09 ERA and 1.07 WHIP over 23.1 innings (four starts) with Triple-A Omaha this season, and will fill in as the Royals need a sixth starter Saturday. It seems likely to be a short stay as the 24-year-old will makes major-league debut, but a quality performance could earn him a second look with Kansas City's pitching staff featuring a 5.21 ERA, second-worst in the AL.