Mauer, talking to a small group of reporters Friday after a workout at Target Field, wanted to convey to fans that he's healthy while clearing up any misconceptions about what plagued him last year.
"I'm healthy, I'm happy," Mauer said. "I can rule out crazy things I've heard like Lyme disease, Lou Gehrig's disease, rheumatoid arthritis, lupus. I think we've heard it all. I don't have any of those things."
Mauer was limited to just 82 games last season, dealing with a range of injuries and illnesses that included bilateral leg weakness, neck stiffness, a viral infection and an upper respiratory infection that turned into a bout with pneumonia, which ended his season on Sept. 14.
The 28-year-old said he visited the Mayo Clinic in Rochester, Minn., after the season, and was officially cleared to begin his workout program -- which he said is much different than in previous years.
"The first thing I did was go down to Rochester, and my goal right away was just to figure out what I can do to pick up things to help me get on the field," Mauer said. "Meeting with nutritionists, meeting with different strength coaches just to see, 'Is there something I can do?' Perry Castellano, our strength coach, him and I went to IMG Academies [in Bradenton, Fla.] for a week and met with some people there just to see if we can pick up anything we can use, and we did."
Mauer, who is headed back to his Florida home next week, said the biggest difference this offseason is that he feels healthy and won't be undergoing any operations like he did last year, when he had surgery on his left knee in December. Mauer said he hasn't started baseball activities yet, but plans to in early January.
"I think a lot of it was doing recovery versus strengthening," said Mauer, who added he's back at his normal weight. "I feel good, and now I can make those strength gains that I need to make before staring those 162 down the barrel. So I'm excited for that. I haven't been able to do that for the last couple of seasons."
Mauer's goal remains to stay healthy enough to be the club's everyday catcher, and he added that one bonus from last season was that he feels comfortable at first base after playing 18 games at the position in 2011.
"I'm the starting catcher, and that's what I plan on doing," Mauer said. "If me going over there to play a few games at first can help keep my bat in the lineup, or help give me a blow physically or mentally, then I'm definitely more open to do that."
Outside of the benefit of seeing some action at first base, it was a lost season for Mauer, who set career lows in batting average (.287), on-base percentage (.360), slugging percentage (.368) and home runs (three).
The backstop said he was "not a happy person" during the season, adding that he was "frustrated" and "angry" given his struggles amid a difficult year for the Twins, who finished with the worst record in the American League.
"I think last year, it was tough," Mauer said. "It wasn't just a tough year for me, personally. I think everybody in this room, we lost 99 games. It's not a good year."
Mauer, entering his ninth season with Minnesota, signed an eight-year deal worth $184 million before the 2010 season. The St. Paul, Minn., native said he feels comfortable in a leadership role, but he also noted that he needs to be more open about his injuries in the future.
"I just feel that, and I've told people in the organization this, if I'm not out there playing, the fans should know why," Mauer said. "People are going to have their own opinions, and you can't control that. As long as my family, my friends and the organization know what's going on, that's what's important to me. You can't control what someone thinks."
Mauer has high hopes for the Twins next season, expressing that health will be key to the club bouncing back.
"I think, obviously, getting guys healthy will help," Mauer said. "Having a Justin Morneau, having a Denard Span and myself, those are three pretty good players right there. Seeing [closer Joe] Nathan go, I mean that's a great player right there, too, and a great guy. What we have in this clubhouse, I mean, it's not a 99-loss team. I can tell you that right now."