Cassel, an eight-year NFL veteran, was initially injured during the fourth quarter of Sunday’s Week 5 matchup with the Baltimore Ravens after taking a vicious shot from Ravens defensive lineman Haloti Ngata.

After the play, Cassel remained on his back for several minutes before staggering to his feet with some help and walking off the field under his own power. He was later diagnosed with a slight concussion and has not been medically cleared to participate in the Chiefs’ next game.

On the season, the former USC QB has been hugely disappointing for Kansas City, who currently sits at the bottom of the AFC West with a 1-4 record.

Through the first five games of the season, Cassel has thrown for more than 1,100 yards but only five touchdowns to nine interceptions. He also has been sacked 13 times and has a quarterback rating of only 66.2, well below his career average of 85.0.

In Cassel’s absence the Chiefs are planning on Brady Quinn to start Sunday at Tampa Bay.

“He’s got some height, he’s got experience, he can throw the ball down the field, he can throw it intermediate,” Chiefs coach Romeo Crennel said of Quinn on Wednesday. “He has a good command of the offense. He knows what’s expected. He knows the calls and can get us into plays, out of plays.

“Now he has to go execute.”

Quinn, a former first-round draft pick who’s 27-years-old and in his sixth NFL season, hasn’t started a game since 2009.

Matt Cassel Injury Update: Chiefs QB Officially Ruled Out For Sunday’s Game is a post from: The Inquisitr