Pollard hit Ridley head-on on the play. Ridley was knocked hard to the ground and fumbled, and the Ravens recovered.
Ridley was taken to the locker room, and the Patriots announced Ridley suffered a head injury and will not return.
It was the latest incident in a string of injuries inflicted by Pollard to the Patriots. In last season's AFC Championship, Pollard was the player who caused Rob Gronkowski's ankle injury.
Pollard was also the Texans safety who tackled Wes Welker after Welker twisted his knee and tore ligaments in the 2009 season finale in Houston.