Coach Jay Gruden says neither player has been cleared for contact, and both will visit an independent neurologist later in the week.
Gruden also expects wide receiver DeSean Jackson to be out for Washington's game against Tampa Bay on Sunday, calling a quicker return from his hamstring injury ''a long shot.''
Williams, a three-time Pro Bowler, missed Sunday's loss to the New York Jets. He entered the concussion protocol last Friday after sustaining what the team originally termed a neck injury in Week 5.
Reed has missed two games. He has 24 catches for 278 yards and a touchdown this season.
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