Three months of rest and treatment have Joe Mauer optimistic again.

"I feel great," the Twins' first baseman said Thursday, at a press conference to announce that Billy Joel will play Target Field in July. "I knew it would take time, and it did, but I'm back to where I should be — getting ready to play."

Mauer ended the season on the bench, suffering from a quad injury that kept getting worse as he tried to keep playing. He appeared in only one game over the season's final two weeks, and admitted during the final homestand that "I feel terrible. I've been feeling terrible for awhile."

He embarked on a treatment program once the season ended that involved regular stretching, a few treatments from trainers, and lots of rest. "I feel real good about where I am now," Mauer said. "This offseason has been very productive for me."

Mauer said he will be fit and ready for the start of training camp in four weeks, and hopeful of bouncing back from a terrible season, both for him and his team. Mauer started the 2016 season strong, playing in each of the Twins' first 42 games, and he was hitting above .300 through the first week of May. But injuries and an increasing problem hitting lefthanders — just a .224 average and a .291 on-base percentage, both career-lows — plagued him the rest of the season. As the injury worsened, Mauer went into a tailspin, batting just .146 (12 for 82) from Aug. 18 on.

Those problems have given manager Paul Molitor something to think about. Mauer sat out only eight games of the Twins' first 125, and the manager wonders if the 33-year-old's up-and-down season had something to do with it. "I think the catching takes its toll, even thought he's not in that position any more. I'm going to try to gauge where he's at a little bit more," Molitor said. "I haven't had a lot of specific conversations with Joe, but … maybe a little less might be a little better."

One thing that could help, Molitor said: The Twins' new front office has already invested in new medical equipment to help evaluate their players. "We're an experimental team," Molitor joked.