Mauer said he first starting feeling the back spasms while taking batting practice before the game, and they kept getting worse. He added it affected him the most when he was out on the field and when he tried to run.
"I felt something in my back and I tried to get loose, but I started to really feel it once I tried to crank it up and get ready for the game," Mauer said. "I tried to get it loose, but the more I kept trying, the more it aggravated it."
But Mauer, who said he'd never experienced lower-back spasms like that before, remained hopeful he'll be able to return on Monday against the Indians in Cleveland.
"I was able to get a lot of a treatment and feel a lot better," Mauer said. "Hopefully it's not too long and I'll get back out there soon. Hopefully I'll get a good night's rest and get in there early tomorrow and get some treatment, and hopefully I'll get out there."
Twins manager Ron Gardenhire expressed similar optimism that Mauer's injury was only minor and that he could return to action on Monday. Mauer has yet to miss a game this season.
"He's doing better after the game," Gardenhire said. "He wanted to play, and I found out about five minutes before the game. He told me it stiffened up pretty good, so he got treatment pretty much the whole game. He could feel it more in the field than on his swing, because he couldn't move. He just got some stiffness in his back but he seems to think he could play tomorrow."
Chris Herrmann took over for Colabello in right field and took Mauer's second spot in the order. Herrmann came up with runners on first and second with one out in the third, but he struck out in his first at-bat of the afternoon. Herrmann ended up going 1-for-4 and made an error in right field on a dropped fly ball that would've ended the game. But closer Glen Perkins was still able to throw a scoreless ninth to preserve a 5-2 win for the Twins.
Mauer entered the game on a hot streak, as he was hitting .404 over his previous eight games and had four RBIs on Saturday, including a three-run homer. After flying out in his first at-bat, Mauer is hitting .296/.393/.374 with two homers, three doubles and 11 RBIs in 29 games.
Rhett Bollinger is a reporter for MLB.com. Read his blog, Bollinger Beat, and follow him on Twitter @RhettBollinger. This story was not subject to the approval of Major League Baseball or its clubs.