Joe Mauer hit .327 with nine home runs and 75 RBIs for the Twins in 2010. (Dave Martin/AP)

FORT MYERS, Fla. -- Twins catcher Joe Mauer caught his first bullpen session of the spring on Saturday morning, and made it clear that he expects he'll be ready for Opening Day.

"I don't think Opening Day was ever in doubt," Mauer said. "Obviously, every day is different -- and we've still got some time before we get there -- and I'm on schedule for Opening Day."

Mauer caught Nick Blackburn's bullpen session at Hammond Stadium, which lasted about 15 minutes. Left-handed first baseman Chris Parmelee stood in as the batter for the session.

It was the first time that Mauer has squatted to catch a bullpen since undergoing offseason surgery on his left knee.

"I'm still getting my strength back," Mauer said. "First time I've been down there [squatting], so I'm not game-ready by any means, right now. But I'm working toward it.

"The knees feel good. It felt better than I thought it would. Just excited to see what happens the next few days."

Although this was the first time that Mauer has taken part in any catching activity in Spring Training, he has taken batting practice and has faced live pitching since he arrived for the start of camp about three weeks ago.

Mauer has been working to regain strength in his left leg, following the offseason procedure to alleviate some irritation that was being caused by the plica band in his left knee. He said his leg is feeling much better now than it did when he first arrived at camp in mid-February, and he's "getting closer" to having full strength in his leg.

"I think this last week was definitely some big strides," Mauer said. "When I first reported to camp, I was a mess. ... But I feel pretty good. I feel like I'm using my leg, and even in hitting, I feel like I'm using more of my back leg -- where I wasn't able to use that a whole lot last year."

Mauer said that he recently finished receiving a series of three injections of synthetic lubricant in his left knee. He could have received up to five injections, but he said that doctors felt three would be enough.

The next step for Mauer will be to see how his legs respond on Sunday after catching in the bullpen. He indicated that he'll likely need to catch a few more bullpen sessions before he's ready to catch in a game, but he will probably be the designated hitter in a spring game before he catches in one.

And that could take place sometime after the Twins' off-day on Tuesday.

"I would like to," Mauer said of serving as the DH in a contest. "Like I said, it's the first day -- and we'll see how we feel tomorrow and the next day. But yeah, if I'm feeling good, then definitely I want to get in there."

Mauer was asked just how much game time he feels he'll need this spring to be ready for the regular season. But rather than worrying about getting a certain number of at-bats, Mauer seems focused on making sure his legs are strong.

"The biggest thing I'm worried about is just getting my legs in catching condition," Mauer said. "Yeah, I'd like to see a lot of at-bats and things like that. But in '09, I was forced to kind of be in a pretty short schedule, I guess. Having gone through that, I think, helps. The biggest goal down here is to be able to catch, and catch back-to-back games."

As for having to wait until March 12 to do his first catching of the spring, Mauer said that it's just been a part of the process in getting himself healthy for the start of the regular season.

"I think it's [longer] than I'd hoped," Mauer said of the recovery process. "But never in doubt was Opening Day. Like anything, I wish I was out there playing the first game of spring. But we've got to be smart about it, and I think we've done that."