Eagles QB Kevin Kolb and LB Stewart Bradley, both of whom suffered concussions in Sunday's loss to the Packers, have failed their concussion tests on Wednesday.
But head coach Andy Reid said both players were feeling better and that each "have made progress" since Monday.
Neither player will practice before Friday, Reid said. That could mean that QB Michael Vick, who had a strong second half replacing Kolb, could start against the Lions on Sunday. The Lions have injury problems of their own at quarterback, with Matthew Stafford (shoulder) out and backup Shaun Hill slated to start.
Bradley suffered his concussion when he collided with teammate Ernie Sims but was allowed to return to the field for a few plays before being removed for the duration. A report Monday suggested that Bradley was not seen by Eagles head trainer Rick Burkholder prior to returning to the field.
Kolb was slammed to the ground by Packers LB Clay Matthews on a scramble and was seen walking off the field slowly. He was allowed to throw three passes after that and was listed as having a jaw injury initially before he too was taken out of the game for good.
Per Reid's guidelines, both players likely would have to practice on Friday in order to play this weekend. The NFL has attempted to take a stronger stance on concussion safety in the past year, requiring teams to consult with an independent neurologist following any kind of head injury. There also are stricter guidelines on players returning to the game after suffering any head trauma.