Joe Mauer was set to start on Tuesday against the Royals, a team he's batting .425 against this season and .355 (in 116 games) in his career.

But the All-Star catcher was hit with back spasms right before batting practice and was scratched from the starting lineup. Ryan Doumit replaced him behind the plate and Josh Willingham moved up into Mauer's customary No. 3 spot in the lineup.

"He was out here early, taking some throws at second base then got ready to hit," Twins manager Ron Gardenhire said. "His back tightened up on him and he had spasms and he's out."

Mauer said he was trying to get loose at the time but couldn't make it to the batting cage.

"It just locked up," Mauer said after the game.