Chiefs' Cassel ruled out for Sunday

Kansas City Chiefs quarterback Matt Cassel has been ruled out for Sunday's game against the Tampa Bay Buccaneers.

Cassel sustained a concussion in last Sunday's loss to Baltimore after taking a vicious shot from Haloti Ngata in the fourth quarter. Following the hit, Chiefs fans began to cheer the injury, garnering much criticism from various media outlets.

Chiefs coach Romeo Crenel said Thursday that doctors have not cleared Cassel. Brady Quinn has been practicing with the first team this week and will start Sunday's game.

Quinn will make his first NFL start since 2009, when he was a member of the Cleveland Browns. Second-year pro Ricky Stanzi will serve as the backup.