Mauer, who was placed on the 15-day disabled list on April 14, met with team doctors on Thursday, but said he's still working on regaining strength in his legs and has yet to begin baseball activities. He also said that a week-long bout with the flu caused him to lose 15 pounds, and added to the weakness he felt in his lower body.
"I'm trying to get that out of everybody, but I've just got to get healthy," Mauer said of a possible timetable for his return. "I'm not where I need to be yet to be on the field and do baseball things. I'm trying to get there as best I can."
Mauer spoke after head trainer Rick McWane told reporters earlier in the day that the All-Star backstop wasn't ready to start the season at catcher even though his surgically repaired left knee, which he had arthroscopic surgery on in December, held up just fine.
"He wasn't strong enough to handle the everyday catching," McWane said. "At the end of Spring Training he said that's the best he had felt, and he was doing fine. He didn't have any issues with his knee at the end of Spring Training, and still, his knee feels good. It wasn't a matter of his knee not being ready, he just, I don't think, had the repetitions catching or anything else. Once the season started, he started to wear down."
Mauer, 28, admitted that the late start to Spring Training -- he didn't start his first game behind the plate until March 19 -- made it difficult to get fully ready for the regular season.
"It was kind of an accelerated Spring Training and I thought I got myself to where, once I got to the beginning of the season, my legs would continue to get stronger," Mauer said. "But it just kind of went the other way, so it's frustrating. But you now, we are where we're at, and I'm just trying to get healthy again."
Mauer, who signed an eight-year deal worth $184 million in 2010, also reiterated that he plans on remaining at catcher, and that he doesn't want to move to another position.
"No, I don't think so," Mauer said when asked about whether he'd be open to a position change. "We're at the point where I'm trying to get strong enough to catch and that's what we're doing. That's what I'm working toward. I just think I can help the team a lot better behind the plate. That's what I signed here to do -- to catch."
Mauer hit just .235 with a .289 on-base percentage and a .265 slugging percentage in nine games before hitting the disabled list. The Twins have struggled in his absence, as they were 9-14 heading into the second game of Thursday's doubleheader against the Rays.
"My teammates want to see me out there, the organization wants to see me out there, and I want to see myself out there," Mauer said. "So it's frustrating when you're not able to play, and I try to encourage the guys while they're here, while they're on the field like they would when I'm out there playing. It's frustrating, I think, for everybody, but especially for me."
Mauer's also expected to need a few rehab games before making his return, but that also has not been scheduled, as Twins manager Ron Gardenhire and general manager Bill Smith will have to work with Mauer and the training staff once he feels healthy enough to play.
"We'll sit down with the schedule and figure out with Joe and Gardy and Bill, and we'll decide how many games he needs to catch," McWane said. "Then he can adjust off of that, too, a little bit, but we haven't gotten to that point yet. He hasn't started doing any baseball stuff yet, so until that happens we can't really decide where he's going to go and how long it's going to be."