KANSAS CITY, Mo. -- Kansas City quarterback Matt Cassel underwent laparoscopic surgery on his appendix Wednesday morning.
The Chiefs at first refused to say why he was not at practice, then said he had a successful appendectomy and would return to work this week.
While there won't be an offiical injury designation until Friday, Cassel is being viewed as questionable for Sunday's AFC West showdown at San Diego, a league source told ESPN NFL Insider Adam Schefter. The team believes there's a 50 percent chance of him playing against the Chargers, the source said.
The Chiefs have a two-game lead over the Chargers in the division with four to play.
Coach Todd Haley said earlier Wednesday it's only a coincidence that third-string quarterback Tyler Palko was promoted off the practice squad Wednesday. The backup is Brodie Croyle, who has not played this season.
In his second season as Kansas City's starter, Cassel has blossomed into one of the league's most consistent quarterbacks. His four interceptions are the lowest total among NFL quarterbacks, and he's a prime reason the Chiefs are 8-4.