A week after Joe Mauer won his fifth Silver Slugger Award as the American League's best-hitting catcher, the Twins announced Monday that it will be his last. Mauer is a catcher no more.

The six-time All-Star will become a full-time first baseman in 2014, after a foul tip ended his 2013 season six weeks early.

"It's one of the tougher decisions I've had to make, but also probably one of the easiest," Mauer said, because the symptoms of his concussion lingered into October. "I really tried to do everything I could to get back out on the field. But it wasn't safe and I wasn't able to do that."

Getting back on the field is what finally convinced the St. Paul native, who had resisted such a position switch for years. A back injury kept him out for a month in 2009, leg injuries cost him half his season in 2011, and he sat out the Twins' final 39 games this year after taking a couple of foul tips off his helmet on Aug. 19. When doctors warned him that another concussion would likely linger at least as long as this one, Mauer had heard enough.

"All it takes is one. That's one of the things I had to realize -- if I said 'no, I'm catching,' all it would take is one foul tip in batting practice and I'm out again," the three-time batting champion said. "I don't want to put myself in that position. I think it's the right decision not only for myself, but for my teammates and the organization."

It was Mauer's decision, general manager Terry Ryan said, but one the Twins -- who still owe their new first baseman $115 million over the next five years -- fully support.

"I'm happy he has chosen to make the transition, but if he decided he wanted to catch, I'm not sure anybody was going to stand in his way," Ryan said. "We had a conversation in October, just about the future. One thing that was apparent, [after] Joe was on the [disabled list] for quite some time, the important thing was his health, and it led from there. Joe did some searching, talked to some people he had a lot of confidence in, and ultimately he got back to me and said he was willing to make the move. I think it's the right decision."

Especially since the Twins have a vacancy at the position, created when Justin Morneau, whose career has been severely impacted by concussions of his own, was traded to Pittsburgh on Aug. 31. Morneau is a free agent now, and Ryan admitted that the possibility of the four-time All Star returning to Minnesota has been lessened by Mauer's decision.

There's also a chance that the Twins might sign a catcher to beef up a position the Twins haven't had to deal with in almost a decade, though Ryan sounded optimistic that the current catchers -- Ryan Doumit, Chris Herrmann, Eric Fryer and especially rookie Josmil Pinto, who batted .342 in 21 games in September -- would be able to handle the position.

Mauer emphasized that he is symptom-free now, and ready to embark on his usual winter workout schedule.