Kansas City Chiefs QB Matt Cassel was drilled by Baltimore Ravens defensive lineman Haloti Ngata and left Sunday's game at Arrowhead Stadium. Cassel was completing a pass to Jamaal Charles in the flat when Ngata, all 340 pounds of him, came crushing into Cassel.

He has a head injury.

As you can see, he was hit by two different players as he went to the ground.

Brady Quinn, the backup, entered the game after Cassel left.

Cassel was down for a couple of minutes surrounded by medical personnel before he was helped up and walked off the field under his own power.

The fans were hoping Cassel was benched -- there was a banner about it earlier in the day -- but this is probably not the way anyone wanted it to happen.

With the way he was playing, Cassel was in danger of possibly being benched anyway.

Fans cheered as Quinn entered the field. His first pass was a 20-yard strike to Dwayne Bowe which put the Chiefs in scoring position.

The Chiefs said Cassel's return was questionable.