Polamalu, who has missed the Steelers' last two games, aggravated the injury during practice Wednesday and has been unable to practice since.

Polamalu, a Pro Bowl safety the last three seasons and the team's highest-paid player, injured the knee Nov. 18 against the New York Jets. He is not having a big year statistically — he doesn't have a sack or an interception — but his versatility is a key to Pittsburgh's zone blitz defense.

The Steelers almost never allow players to play in a game when they are physically unable to practice on Friday — one reason why wide receiver Santonio Holmes struggled through the team's workout on a sprained right ankle.

Holmes, also out for two games, continues to have pain in the ankle and was urged earlier this week to sit out another game. Holmes said the game against New England (12-0) is too important to the Steelers (9-3) to miss and he plans to play.