Philadelphia Eagles coach Chip Kelly confirmed Monday that quarterback Nick Foles has a concussion.
Foles' playing status will not be determined until he passes the NFL's mandated concussion protocol.
Michael Vick, who was the starter until injuring a hamstring Oct. 6, did not play Sunday and it is uncertain when he will be healthy enough to return.
Kelly would not say who will take first-team snaps in practice this week when the Eagles prepare for this Sunday's game against the New York Giants.
"I don't know until we get here and run around a little bit (Tuesday) morning," Kelly said. "Tomorrow is a lifting day, so they'll lift before we get out onto the field. Mike was in for treatment. Nick was here. So we'll make a determination when we get to tomorrow."
Foles completed 11 of 29 passes for 80 yards in the 17-3 loss to the Dallas Cowboys.
Rookie Matt Barkley, who replaced Foles, was 11 of 20 for 129 yards with three interceptions. He is the only healthy quarterback on the team's roster. He could start if Vick or Foles cannot play.
"My decision on who our quarterback is is based on health," Kelly said. "Right now, I don't who's healthy or who's not healthy. Until we find out who's healthy, it doesn't help anybody to say, 'That guy's our starter.' It doesn't help the situation."
Vick said last week his hamstring was improving but the injury was more serious than he thought. He was deactivated Sunday after pregame warmups.
"He said it feels it's moving in the right direction," Kelly said. "It will be interesting to see where he is from a standpoint of running around a little bit tomorrow morning."
Kelly said Foles seemed to be getting better after speaking with him after the game.
"He seemed like he's doing well," Kelly said. "But all that stuff, and rightly so, there's a protocol and a system he goes through."