Williams will take the place of rookie running back Chris Thompson, who is out for the remainder of the season because of a torn labrum in his left shoulder.
Williams is expected to compete primarily for playing time on special teams. The undrafted rookie out of Connecticut recorded seven catches for 51 yards and one punt return for 29 yards during the preseason.
The Redskins have struggled mightily in the return game, and Coach Mike Shanahan said on Friday that the team would continue to experiment with punt returners.
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● Tuesday morning, Mark Bullock looks at the fourth-down pass to Santana Moss against the Vikings.
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