It is expected that Fitzpatrick will be placed on injured reserve, the sources said.
Kyle Allen will be Heinicke’s backup in the game.
Fitzpatrick left Sunday’s 20-16 loss to the Los Angeles Chargers in the second quarter after being leveled by Chargers linebacker Uchenna Nwosu. He is expected to have an MRI on Monday to see whether he suffered a hip subluxation and to determine the severity of the injury.
Heinicke, a fan favorite after his strong showing in a playoff loss to the Tampa Bay Buccaneers, replaced Fitzpatrick. He finished 11-for-15 for 122 yards and a touchdown on Sunday.
ESPN’s John Keim contributed to this report.