Mathis went down in a heap late in the second quarter when running back LeSean McCoy rolled into him from behind. Mathis was down for several minutes and needed help from trainers to get off the field. He was carted to the locker room for more tests and will not return.
Mathis started all 16 games each of the last two seasons for the Eagles.
Jason Peters, Mathis, Jason Kelce, Todd Herremans and Lane Johnson started every game last season. Continuity and consistency helped them develop into one of the NFL's top units. But Johnson will miss the first four games because of a suspension for violating the NFL's policy on performance enhancing drugs.
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