Mathieu (quadriceps) will not return Sunday against the Steelers, James Palmer of NFL Network reports.
Mathieu exited in the second half with the injury. The severity of the injury is unknown and whether Mathieu's inability to return has more to do with the score and time left in the game or the extent of the injury itself. Daniel Sorensen will likely see extra work for the remainder of the game. After the game, coach Andy Reid clarified that Mathieu's injury is a quad contusion, per Nate Taylor of The Athletic, so Mathieu is unlikely to miss additional game action as a result of the injury.