Quarterback Robert Griffin III #10 of the Washington Redskins looks on during warmups before playing against the Jacksonville Jaguars at FedExField on September 3, 2015 in Landover, Maryland.Patrick Smith/Getty Images
Washington quarterback Robert Griffin III is still awaiting medical clearance to return from a concussion he sustained three weeks ago.
Griffin or Colt McCoy will back up starter Kirk Cousins on Sunday when Washington opens its season against the Miami Dolphins.
Coach Jay Gruden said Thursday he has "no idea" why the team has yet to receive a written response from the independent neurologist who examined Griffin this week. On Wednesday, he said he expected to receive it by the end of the day.
Gruden suggested he could wait until game day to announce Washington's backup.
Griffin lost his starting job to Cousins early last week and has missed Washington's final two preseason games. Gruden had appointed Griffin this season's starter in February.