Although Mauer was not available Monday, he is considered day-to-day.
"He actually walked in standing straight up, and that was a good thing, 'cause yesterday he was bent over a little," Twins manager Ron Gardenhire said.
Gardenhire had little concern about the potential for Mauer's sore back to linger.
"He's had spasms before," Gardenhire said. "We just have to ride it out, let the trainers do their thing.
"I think if you've had back problems, we all understand that. It's a spasm, not some kind of crooked-spine thing."
Chris Colabello took Mauer's place at first base on Monday. Outfielder Sam Fuld hit second in Mauer's usual spot in the lineup.
Stephen Ellsesser is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.