Kansas City, Mo. ? The offensively weak Kansas City Royals sent DH/first baseman Billy Butler to Triple-A Omaha on Thursday, hoping to kick-start a feeble attack that had contributed to their 10-game losing streak.

Coming up from Omaha was infielder Mike Aviles, a 27-year-old non-roster invitee who was hitting .338 through 50 games. Aviles got the start at shortstop against Minnesota on Thursday night, replacing slumping Tony Pena Jr.

The Royals also put right-hander Leo Nunez on the 15-day disabled list with a strained muscle in his right side and called up left-hander Neal Musser, who was 0-4 with six saves and a 3.07 ERA in 19 relief appearances at Omaha.