Aviles is expected to play shortstop at Omaha as he continues to build arm strength after undergoing reconstructive elbow surgery last June. He was ahead of schedule in his comeback this spring. However, in the first five games this season, Aviles appeared briefly just twice, once as a pinch-runner and once as a pinch-hitter.
"He needs to play right now," manager Trey Hillman said.
Aviles hit .471 (24-for-51) in the Cactus League after missing most of last season because of his surgery. Most of the spring he played second base to avoid putting too much stress on his throwing arm.
"I think he's throwing good. Mike, obviously, wasn't given any opportunity to play offensively," Hillman said. "I like our look defensively. We've had a couple of miscues but I think our infielders have made a couple of key plays that have kept us in games that we've won."
The Royals made the move after being assured that pitcher Kyle Farnsworth would not have to go on the disabled list because of a stiff right shoulder.
Now the Royals have a pitching staff of 13, including five starters. The bullpen had a rough time in the first five games, compiling an 11.05 ERA, taking two losses and blowing three saves.
"We need to keep as much pitching as we can right now until we get this bullpen situation ironed out and get some consistent production and figure out exactly what the rotation's going to be out of the bullpen," Hillman said.
With Aviles departing, the Royals have just three extra players in infielder Willie Bloomquist, outfielder Mitch Maier and catcher Brayan Pena.
"Obviously when you get rid of a position player to keep pitching, you don't have as much flexibility so I'll have to be more cautious with the position player moves that I make," Hillman said, "and remember that we don't have that extra bullet."
He noted that Bloomquist is capable of playing every infield position and that Maier or Pena could play the infield corners in a pinch.
Aviles, the Royals' Player of the Year in 2008 when he batted .325, would supplant Irving Falu as the Omaha shortstop. He took his demotion in stride.
"Disappointed, which we knew he would be," Hillman said, "but he also expressed the trust that he has in what we're doing and why we're doing it."