NFL Media Insider Ian Rapoport was told by a source informed of the injury that Manning "will start Sunday" after testing revealed a simple aggravation of the ankle injury he's dealt with all season.
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Del Rio said Manning "will practice" this week, and we'd be surprised if he showed any signs of the injury by Sunday.
"I'm pretty sore," Manning told reporters after knocking off the Chargers. "They kind of got me twice in kind of that lower area."
Outside of the neck injury that sidelined Manning for the 2011 season, he's been an iron man under center, playing through a host of nicks and bruises. He'll be ready for Kansas City.