Mauer, 31, suffered the injury in the fourth inning against the Kansas City Royals on Tuesday night.
Mauer, who has hit safely in 12 straight games, is hitting .271 with 17 doubles, two homers and 28 RBIs in 76 games this season.
To take the place of Mauer on the 25-man roster, the Twins recalled first baseman/outfielder Chris Colabello from Triple-A Rochester.
Colabello played in 36 games for Rochester, hitting .275 (36-for-131) with eight doubles, six home runs and 27 RBIs. He played 40 games with the Twins earlier this season, hitting .232 (35-for-151) with 10 doubles, four home runs and 30 RBIs.