Mauer, who played first base in the first game of a split doubleheader before catching the second game on Monday, was given the day off from behind the plate, with Drew Butera catching left-hander Francisco Liriano.
"He's moving pretty good," Twins manager Ron Gardenhire said of Mauer. "We've got him playing first base today. We're trying to take a little load off his legs. He took a beating in that second game. But yeah, he's been coming along swinging the bat. I think his legs are feeling better underneath him, and you can tell the bat head is starting to get out there. He's firing the ball all over the place."
Mauer picked up six hits in eight at-bats on Monday to raise his batting average to .290 on the season. He entered Tuesday's game hitting .393 with a .485 on-base percentage in July.
"I feel pretty good at the plate," Mauer said. "I'm just trying to hold onto that feeling. I'm just trying not to do too much. I'm seeing the ball a lot better, and getting my foot down and feeling a lot more relaxed."