DETROIT – An apparently serious injury to Detroit Lions star Jack Campbell halted the game against the Vikings for several minutes on Sunday.Campbell, a Pro Bowl linebacker and one of the leaders of the Lions defense, stayed down on the field after tackling Vikings tight end T.J. Hockenson. He remained on the field for multiple commercial breaks, surrounded by the entire Lions roster and many Vikings players, before being strapped onto the medical cart and driven to the tunnel. No specific details about the injury have been released yet. Several of Campbell’s defensive teammates were emotional following the injury. The...