Twins catcher Joe Mauer on Friday acknowledged for the first time that he went to the Mayo Clinic in Rochester in late April for a battery of tests, and that problems with his right shoulder are affecting his throwing.

Mauer said he went to Rochester shortly after visiting his specialist at Johns Hopkins Hospital in Baltimore on April 18, to make sure he didn't have any more serious problems. Mayo's findings were similar to what the Twins' medical staff diagnosed, which was bilateral leg weakness.

Mauer was diagnosed with that April 14. About the same time, he also came down with a viral infection that caused him to lose 15-20 pounds and feel even weaker.

"We just wanted to make sure everything was good," Mauer said. "We went down there and it was a good visit. We tried to keep [the visit] as quiet as we could."

Mauer knows rumors have been flying throughout the Upper Midwest that he might have a more serious condition. On Friday, Mauer ruled that out, indicating his exam at the Mayo Clinic was thorough.

"That's kind of what they do. ... They check for everything," he said. "It was a good visit."

The check included Mauer's left knee, which was operated on during the offseason, and right shoulder. His arm strength is down as a result of problems with his legs, but he said he is working out daily and his strength is improving.

"It's tough to explain," Mauer said. "Your body compensates. You try to play through it, and it started to get bad.

"[The shoulder] wasn't functioning the way it should. I've played through a lot of things, but when you're hurt it is a different story."

Mauer believes everything still stems from reporting to spring training following knee surgery, trying to put himself on an accelerated program to get ready for Opening Day and underestimating how long he needed to get game-ready.

Mauer has played in only nine games, batting .235 with one double and four RBI.

He leaned on a bat near his dugout Friday as he talked about how difficult it has been to be sidelined while the Twins have the worst record in baseball. The team certainly could use the three-time American League batting champion in the lineup.

He took batting practice with his teammates for the first time since going on the DL and also did some throwing before Friday's game against Toronto. He believes he is headed on the right path.

But Mauer still couldn't predict when he will take the next step -- going out on a minor league rehabilitation assignment.

"I wish I could be out there tonight," he said. "It is frustrating to not be able to play, and even more frustrating when the team is not playing well."

Manager Ron Gardenhire said he believes it is important for Mauer to do a many activities as possible with teammates to help him through the rehab process, so Friday was an important day.

"Baseball activities are important," Gardenhire said. "Taking BP, being with the guys, doing the work out on the field. And I want him to be involved in that to get his mindset that it's time to get back on the field when he is healthy."