Mauer was taken out of Sunday's win against Baltimore in the third inning when his back tightened. Manager Ron Gardenhire said Monday that Mauer has improved, but the team wants to give its star some extra rest.
Gardenhire said Mauer has been receiving treatment and the team does not believe the injury is serious.
A six-time All-Star catcher who moved to first base on a full-time basis this season, Mauer is batting .296 with two homers and 11 RBIs in 29 games. He's hitting .393 (11-for-28) since April 25.
Chris Colabello took Mauer's spot at first in Monday's series opener against Cleveland. The 30-year-old Colabello is batting .274 with three homers and a team-leading 27 RBIs.