Troy Polamalu, the 2010 Defensive Player of the Year, was knocked out of Sunday night’s game vs the Kansas City Chiefs on the Steelers first defensive series of the game. Polamalu took a blow to the head while trying to tackle Chiefs massive o-lineman Steve Maneri. Polamalu remained on the sideline for the rest of the game. It is the second time this season Polamalu has suffered concussion like symptoms.