Chiefs quarterback Matt Cassel underwent an appendectomy Wednesday, putting his availability into doubt for Sunday's key divisional game at San Diego.
Hours before making the announcement that Cassel had undergone successful surgery, the Chiefs promoted quarterback Tyler Palko from the practice squad to the active roster. If Cassel can't go, backup Brodie Croyle would start, with Palko backing him up.
The team said that Cassel was expected to return to work "this week," but did not immediately address his status for the Chargers game. It would be unlikely that he could play that soon after an appendectomy, however. Steelers quarterback Ben Roethlisberger had an emergency appendectomy just prior to the 2006 season -- he went under the knife on Sept. 3, missed the Steelers' Week 1 game four days later (a Thursday night contest), then returned on Sept. 18 for Pittsburgh's Week 2 game.
Front-running Kansas City has a two-game lead over the Chargers in the AFC West with four games remaining.
Cassel, who was named AFC Offensive Player of the Month for November, has thrown for eight touchdowns and one interception with a 93.4 passer rating against AFC West teams this season.
Kansas City beat the Chargers in the season opener and is going for consecutive wins against its division rival for the first time since 2003.