Carson Wentz could need three months to heal the stress fracture in his back.
During a tense back-and-forth with the media, Doug Pederson said that it's an injury that has "evolved over time" and will not require surgery.
Wentz is being listed as questionable and will travel with the team for Sunday's game against the Los Angeles Rams.
Wentz, however, is unlikely to play again this season.
The fracture was discovered as a result of a scan on Tuesday, according to Pederson.
"Until you do a scan, you don't know," he said, but added "we do a lot of testing each week on a lot of players."