Foles, a third-round pick out of Arizona last spring, has been starting at quarterback since Michael Vick suffered a concussion Nov. 11.
In four games (three starts), Foles is 81-of-133 passing for 793 yards, two touchdowns and three interceptions. That includes a 22-of-34 effort for 254 yards in the Eagles' 38-33 loss to Dallas Sunday night.
Philadelphia has lost eight consecutive games after starting the season 3-1. Only two NFL teams have fewer wins this season.
"This was my decision," Reid said when asked if there was any external pressure driving his choice of quarterback. "If there's one great thing about the Eagles organization ... it's that they've allowed me to make the decisions."
The Eagles play at Tampa Bay Sunday and against Cincinnati Dec. 13 before ending the season with NFC East games versus Washington at home and in New York against the Giants.