Mauer, who won his second batting title last season, had surgery Dec. 22 to remove a blockage from one of his kidneys.
"I still have all of my parts intact," Mauer said. "It was something I've had since birth."
"I don't know what I'm going to do," Mauer said as his teammates filtered into the Hammond Stadium clubhouse. "But I'll find out in a little bit."
Mauer said he hoped to be ready by Opening Day.
"I'm going to take it slow," Mauer said. "I think that's the right thing to do."
Mauer admitted to playing through pain for parts of last season, not knowing why. The pain increased during the offseason, prompting a series of tests and the subsequent surgery at the Mayo Clinic in Minnesota.
"I was poked and prodded," Mauer said. "I definitely didn't look good. I'm glad I feel fine now."
The 25-year-old Mauer hit .328 with nine home runs and 85 RBI in 146 games last season. In 2006, he hit .347 and became the first catcher to win a batting title since 1942, when the Boston Braves' Ernie Lombardi accomplished the feat.
Mauer, down to 220 pounds from last year's listed 230, said the surgery limited his offseason conditioning.
Twins starting pitcher Scott Baker did not see a problem with Mauer missing the first part of spring training drills.
"For the most part, everybody on our pitching staff is familiar with him," Baker said. "As far as that goes, I think we're OK, as far as not having him right off the bat for the early part of spring training."
Baker went 11-4 with a 3.45 ERA last season. He credited some of his success to having Mauer behind the plate for about 75 percent of his outings.
"He takes a lot of pressure off us as far as the running game goes," Baker said. "When he's back there, their running game is pretty much nonexistent.
"He's a very blessed man, and very humble. We're fortunate to have him."
Baker said he had no doubt Mauer would be ready to go at the start of the regular season.
"It doesn't matter what he's doing, he's going to be good at it," Baker said.
Relief pitcher Luis Ayala, who spent last season with the New York Mets and Washington Nationals, reported to camp Sunday but has yet to sign a contract as the Twins decide whom to take off the 40-man roster. Ayala has agreed to terms on a one-year deal. He went 2-10 with a 5.71 ERA in 81 appearances last season.