"The tightness in Felipe Paulino's back started Tuesday and grew worse overnight. By the time he arrived Wednesday at the Royals' clubhouse, he knew couldn't make his scheduled start against Detroit at Comerica Park.

"It just happened (Tuesday) before practice," Paulino said. "I got up today, and it was real bad. I can't pitch with this. Hopefully, it will get better today with treatment. I hope it will just be a few days."

The Royals replaced Paulino by pulling little-used rookie Nate Adcock from their bullpen. Adcock made two previous starts in May because of injuries to other starters but has pitched only 7 1/3 innings in four appearances since July 27.

Adcock responded by pitching into the sixth inning and handing a two-run lead to the bullpen. He settled for a no-decision when the Tigers rallied for a 5-4 victory by scoring three runs in the eighth inning.

Paulino is 2-6 with a 3.83 ERA in 17 games, including 16 starts, since arriving May 26 from Colorado in a cash transaction.

"He should be back in a day or two," Yost said. "He's got back spasms. Everybody has back spasms (occasionally). It just locked up on him.""