Arizona Cardinals defensive end Calais Campbell has been carted off the field at San Francisco with an apparent right leg injury.
Campbell was injured when his leg buckled beneath him as he helped bring down Frank Gore on a 1-yard gain late in Sunday's game.
A large group of players from both teams knelt down around him on the 25-yard line as Campbell was attended to with 4:56 remaining and Arizona trailing the 49ers 29-20. Former Cardinals wideout Anquan Boldin put his arm around a member of Arizona's medical staff.
A star member of the Arizona's stingy, much-improved defense, Campbell had four tackles and a half-sack Sunday.
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