Phillies physician Michael Ciccotti said Wednesday evening that Moyer "is in no way seriously ill."
"He's very comfortable," Ciccotti said. "He's quite fine. He's walking. He's eating. He's completely comfortable and fine. We're just taking appropriate precautions, and also wanting to do what we can to make sure he's on track for Spring Training."
Ciccotti said Moyer started to feel an increase in pain over the weekend, which prompted him to fly to Philadelphia on Tuesday to visit Hahnemann University Hospital, where Bill Meyers performed the surgery Oct. 2.
Moyer stayed the night at Thomas Jefferson, where he is expected to remain, possibly through the weekend for continued evaluation.
"We're in the midst of evaluting him and treating him for this increase in pain," Ciccotti said. "He's getting some tests, an MRI. He's continuing to exercise as his comfort allows. That's really where we're at right now."
Moyer had been hospitalized with a blood infection Oct. 7, five days following his surgery. He spent three nights in the hospital before being released.
Ciccotti said Moyer's current symptoms don't seem to be related to last month's blood infection, but he hasn't ruled it out. Moyer has had blood tests as part of his evaulation.
So what could have happened to put Moyer back in the hospital?
"You can restrain that area during the recovery or rehabilitation period," Ciccotti said. "That's where the MRI is helpful because it can help us determine if that's the case and then that's just a matter of adjusting his rehab and his therapy."
Ciccotti said Moyer's rehab following surgery had gone "very well," and despite his setbacks, he said Moyer still could be ready to participate at the beginning of Spring Training in mid-February.
"The recovery from this surgery is such that normally it's three months or so," he said. "He had it in early October. Really, he would be recovered from this surgery sometime in January, well before Spring Training. So having been in the hopsital, and now a few more days in the hospital, that may delay his full recovery, but he's still on a timeline that would allow him to participate in Spring Training.
"It's possible it could be a little bit later than [mid-February], but he's still on the timeline that would allow him to participate in Spring Training with hopefully minimal effects on his early Spring Training participation."
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.