Without actually saying the words, head coach Andy Reid essentially has admitted that some of the team's younger players have not played up to par, which can be one reason to explain the Eagles' less-than-stellar defensive performance this season. The defensive line has been a fairly stout unit in most respects, and it's the most senior group in terms of experience. But the linebacker corps and the secondary — namely the safeties — have left a lot to be desired. The quintet of LBs Jamar Chaney, Moise Fokou and safeties Nate Allen and Kurt Coleman (all in their first, second or third seasons) have logged the most time in those spots this season, and some team observers have traced the lack of success to the play up the middle. Chaney has settled down a bit inside, but he has been playing catch-up all season after switching from middle linebacker in former coordinator Sean McDermott's system last season to the strong side in training camp this year back to the middle in new coordinator Juan Castillo's defense when rookie Casey Matthews proved to be in over his head at that spot.