Kansas City, MO (Best E Casino) - The Kansas City Royals optioned designated hitter and first baseman Billy Butler to Triple-A Omaha on Thursday.

Butler, in his second season with the Royals, was hitting just .263 with one home run and 18 runs batted in through 53 games this season. The 22-year-old played in 92 games for Kansas City in 2007, and hit .292 with eight homers and 52 RBI.

His roster spot will be taken by the hot-hitting Mike Aviles, whose contract was purchased on Thursday. In 50 games with Omaha, Aviles hit .338 with 10 homers, six triples, 42 RBI and a .634 slugging percentage. The 27-year-old has split time between shortstop (18 games) and second base (32 games).

The Royals made two other moves on Thursday: pitcher Leo Nunez was placed on the 15-day disabled list, retroactive to May 28, and Neal Musser was recalled from Omaha.