Source: Polamalu likely out 1 month

Pittsburgh Steelers safety Troy Polamalu is expected to be sidelined about a month with a strained ligament in his knee, a source close to the situation told ESPN's Adam Schefter.

Polamalu, who did not play in the Steelers' 27-24 overtime loss in Kansas City, injured a knee ligament while tackling Cincinnati's Cedric Benson last Sunday. He missed four games after hurting a different ligament during Pittsburgh's opener.

Polamalu's recent injury will not require surgery.

He wore a heavy brace as he watched practice this week.

Adam Schefter is ESPN's NFL Insider. Information from The Associated Press was used in this report.