Turns out, all he had to wait was a couple of days.
Adcock will get a spot start on Sunday for the Royals in the Interleague series finale against the D-backs at Kauffman Stadium.
The right-hander was pressed into duty when lefty Everett Teaford went on the 15-day disabled list with a lower abdominal strain on Saturday.
Adcock last worked a strong five innings of relief in Wednesday night's 15-inning, 4-3 loss to the Orioles. He gave up the decisive home run to Adam Jones in the 15th, but he and right-hander Vin Mazzaro were sent down to Omaha because fresh arms were needed in Kansas City.
In four games with the Royals, Adcock is 0-1 with a 2.51 ERA. He'll be starting on Sunday after three days' rest. In his five innings against the Orioles, Adcock threw 52 pitches.
"Nate did a great job. He had good stuff," Royals manager Ned Yost said after the 15-inning marathon. "Besides [the home run pitch to Jones], his sinker was really good, getting a lot of ground balls. He was on the attack, throwing strikes, holding them right there and giving us opportunity after opportunity to come in and try to find a way to score a run."
For the D-backs, it'll be Wade Miley on the mound. In his last outing, the 25-year-old shut down the National League West-leading Dodgers for 6 2/3 innings, allowing just one run on eight hits for the win.
"I was commanding the fastball early in the count and I was able to work off of that," Miley said. "[D-backs catcher Miguel Montero] called a great game. We didn't get away from the plan. Everything he put down we went with and it was fortunate that it worked out."
Royals: Perez ahead of schedule
Catcher Salvador Perez might be back in the Royals' lineup about two weeks earlier than expected.
Perez, who had knee surgery in Spring Training, originally was projected to be out until about the break for the July 10 All-Star Game in Kansas City. Now it appears he could return by late June.
Perez took batting practice on the field for the first time on Friday after a period of swinging in the indoor cages. He's also been catching side sessions with pitchers in the bullpen.
Perez is likely to leave for the Royals' facility in Surprise, Ariz., next week.
D-backs: Breslow becoming bullpen force
D-backs reliever Craig Breslow is focused on consistency after making adjustments in Spring Training this season.
Breslow has a dominating 1.31 ERA in 18 appearances, while opposing hitters are batting just .155 against him.
Breslow hasn't allowed a run in 9 1/3 innings this month. He's only allowed four hits and one walk, all while striking out eight batters.
Willie Bloomquist has logged four straight multi-hit games entering Sunday's series finale.
The Royals are 5-16 at home and 11-7 on the road.