Cassel, who the Chiefs acquired in a trade with New England this offseason, was hurt Saturday night in an exhibition game against Seattle. The injury is not expected to require surgery because MCL injuries usually heal on their own.
However, the injury means Cassel could miss the Chiefs' season opener at Baltimore on Sept. 13. If Cassel can’t play, Tyler Thigpen(notes) is expected to start the season. Thigpen, who had been the subject of trade rumors earlier this week, played in 14 games last season when the Chiefs went through injuries at quarterback. He finished the season with 18 touchdown passes, 12 interceptions and a quarterback rating of 76.0.
Cassel also suffered an ankle injury, but that was not considered as serious as the MCL injury.