Stevan Ridley injures head on Bernard Pollard's hit

New England Patriots running back Stevan Ridley didn't return to Sunday's AFC Championship Game after sustaining a head injury during the fourth quarter of his team's 28-13 loss to the Baltimore Ravens.

Ridley was on the receiving end of a nasty helmet-to-helmet hit from Ravens safety Bernard Pollard.

With 12:53 remaining in the fourth quarter and the Patriots trailing 21-13, Ridley was walloped by Pollard at the end of a 5-yard run. Ridley lost the ball as he went to the ground, and it was recovered by the Ravens. An official review upheld the ruling.

Ridley remained down for several minutes before walking off under his own power and heading into the locker room, likely for concussion testing. The Patriots later ruled him out with a head injury.

The Ravens took over and needed just four plays to cover 47 yards for a touchdown that ballooned their lead to 15 points with 10 minutes to play.

Pollard already was a villain in Patriots lore before his crushing hit on Ridley. Here's a refresher of previous incidents involving Pollard and the Patriots:

»September 2008: Pollard, then with the Kansas City Chiefs, crashed into Tom Brady's planted left leg. Brady was lost for the season with a torn anterior cruciate ligament.

»January 2010: Pollard, then with the Houston Texans, closed in on Wes Welker, who tore his ACL while trying to cut away from the safety.

»January 2012: Pollard, now with the Ravens, dragged down Rob Gronkowski, who sustained a high ankle sprain. Gronkowski was knocked out of the game and limited in a Super Bowl XLVI loss.

Follow Dan Hanzus on Twitter @DanHanzus.