Ryan Clark officially was ruled out Sunday against the Washington Redskins because of a concussion.
The Pittsburgh Steelers safety suffered the head injury on a third-quarter tackle. Clark was replaced by Ryan Mundy, leaving Pittsburgh without both of its starting safeties in a 27-12 victory.
Will Allen started in place of Troy Polamalu, who was ruled out again this week because of the strained calf he reinjured in Week 5.
The Steelers weren't tested by the Redskins' passing game, but losing Clark against the New York Giants next Sunday would only further compromise the team's back four. The 33-year-old safety has played in six consecutive games since missing the season opener.
UPDATE: Clark told CBSSports.com's Jason La Canfora in a text message that he feels good and recalls the details of the game, including his hit on Redskins rookie quarterback Robert Griffin III.
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