The reigning AL batting champion isn't sure when he'll be able to return.
"We really don't have a timetable," Mauer said. "It all just depends on how I feel. Hopefully, it will be sooner than later. There's good days and bad days.
Mauer has inflammation in the sacroiliac joint, which connects the spine to the pelvis. Mauer traveled to Baltimore on March 14 to seek a second opinion for the injury.
"We know it's in there," Mauer said of the inflammation. "We just have to get it out."
Mauer had offseason surgery Dec. 22 to remove a blockage from one of his kidneys, but he said this injury isn't related to that. The two-time All-Star has been limited in spring training because of his back problems and hasn't played in any games.
"I just have to get healthy," Mauer said. "I don't think I'm ready to get out there and play any games. I know it's getting closer. I really don't know if I'm going to be there or not."
Twins general manager Bill Smith said the club did not view the injury as a long-term problem, but said doctors do not have a timetable for Mauer's return.
"All of the doctors have confided and spoken together," Smith said. "We'll get him on the field as soon as we can. Everybody's on the same page. We're trying to reduce that inflammation."
Mauer said he hoped the pain wouldn't linger or return after he gets back to playing.
"Right now, we're just trying to get it out of there," he said. "I don't think it's something that will be reappearing."