McGee has been experiencing pain recently in and around his left tibia. The Nuggets said he underwent a CT scan to try to determine whether a stress fracture was the source of the problem. However, there was no immediate indication of a stress fracture.
McGee was scheduled to have an MRI on Tuesday and doctors will review the results of both exams before formulating a diagnosis.
Coach George Karl said Timofey Mozgov would likely see increased minutes off the bench in the absence of McGee, who is averaging 10.1 points and 4.8 rebounds per game as one of the Nuggets' top reserves.
Karl said McGee has been a force for the Nuggets in the paint and his loss would be felt.
"It takes away the ability to get four or five dunks and the ability to have a defensive force in the middle," Karl said. "I think he is having a good year for us. We've got him a number where we are getting what we want out of him, and he is building towards becoming bigger and better."