Breaking down the Chiefs' game

Posted by ESPN.com's Bill Williamson

A look at the Chiefs' 14-10 loss to visiting Seattle:

The Chiefs didn't say what Matt Cassel's injury was other than he has a leg injury. It's believed that Cassel has a knee injury that is not overly serious. He departed after being sacked on the third play of the game and he did not return. The Chiefs are expected to next address Cassel's situation Monday. The Chiefs start the season in 14 days at Baltimore.

Cassel was brought to Kansas City for stability at the position after the Chiefs saw two quarterbacks do down with injuries last season.

Cassel's injury Saturday night was another indication of how the team needs much better offensive line play. This unit is a liability, and Cassel, when he returns, is going to have to deal with playing under constant pressure.

The Chiefs have to find a way to protect the quarterback better or the injuries are going to pile up.

With Tyler Thigpen replacing Cassel, it makes you wonder if the team will still consider trading him if Cassel is going to miss any time.

Matt Gutierrez, who is competing with Thigpen to be the No. 3 quarterback, completed 10 of 13 passes. Brodie Croyle didn't play Saturday night because the Chiefs wanted to get Thigpen and Gutierrez more playing time, but Croyle still appears to be the choice as the No. 2 quarterback.

The Chiefs were terrible on third down, converting just 1 of 10 opportunities.

Top pick Tyson Jackson was terrific and showed his play-making ability.

Newly signed receiver Ashley Lelie showed a spark and he had 52 yards on four catches. Lelie has some ability and the Chiefs need receivers, so he may have a chance of making an impact.

In addition to Cassel, standout cornerback Brandon Flowers and receiver Devard Darling were injured. There injuries are not known.

Rookie kicker Ryan Succop has been good, but he missed a 27-yard field goal Saturday night.