KANSAS CITY, Mo. — Alberto Callaspo was placed on the disabled list for undisclosed reasons by the Kansas City Royals today, one day after being arrested for suspicion of driving under the influence.

To take his place on the roster, Kansas City recalled first baseman-designated hitter Billy Butler, a top prospect who was sent down to Triple-A Omaha a month ago to work on his attitude and game.

"It takes a lot of humility. You learn a lot about yourself," Butler said. "I know I had things to work on, emotionally and everything. I'm just glad to be back. I'm happy with my life."

Callaspo, a utility infielder who has appeared in 42 games, was arrested early Friday morning and spent about seven hours in jail before being released on a signature bond. The Royals were evasive about what he would do.

"Alberto is going on the disabled list for evaluation and treatment of an undisclosed medical condition," manager Trey Hillman said. He declined to elaborate.

"I've already given the statement," he said.

When questioned again, Hillman did say he felt Callaspo, who hit .290 in 100 at-bats with four RBIs, would return.

"Yeah, I think he'll be back at some point. He's got a good attitude right now. You can't have somebody do what he's going to do without having a good attitude.

"That's it. That's it. That's all I'm saying."

The 22-year-old Butler is one of the Royals' top prospects. He got off to a hot start but tailed off and was sent down on May 29. He hit .263 with 18 RBIs in 53 games for the Royals.

Butler seemed to regain his stroke at Omaha, hitting .337 with five homers in 101 at-bats.

"A week ago he was hitting close to .400," Hillman said. "I'd say his confidence as far as being able to hit the baseball should be pretty high."

Butler said he was back with a brand new attitude.

"I want to do the best I can, no matter what I do. If I don't do a good job, I've got to stay even keel. I hit a bad spurt with my bat and my confidence at the plate. I know I'll be back. my confidence is back."

When he was sent down, the Royals were nearing the end of a 12-game losing streak. On the day he returned, they'd won 11 of 12.

"We're on a roll here and I don't want to be a distraction from that. I'm just going to try to blend in and help out," he said.