The Kansas City Chiefs' dim playoff hopes were dealt another blow Friday.
Team trainer Rick Burkholder told reporters that Smith suffered the injury after taking a hit during the third quarter of last week's loss to the Pittsburgh Steelers. Smith won't need to undergo surgery and is expected to make a full recovery.
Burkholder said the exact nature of the injury was not immediately obvious until after Smith underwent a body scan Thursday. Smith managed to practice Tuesday and Wednesday despite feeling some discomfort.
Chase Daniel will start at quarterback for the Chiefs, who need a little help to make their postseason aspirations a reality. Kansas City must beat the Chargers and hope the Baltimore Ravens and Houston Texans lose their games in order to make the playoffs. The Chargers would make playoffs with a win.
Smith has passed for 3,265 yards and 18 touchdowns this season. If the Chiefs make the playoffs, Smith also would sit out the postseason opener.
The Associated Press contributed to this report.