It think talk of 2nd and 3rd string players playing, and not starters nowadays is a bit misleading. So many players are situational, especially on Defense, thats why Teams are crying out for top-class nickelbacks. What might be a player 2nd or 3rd on the depth chart, could be almost indispensable for some Teams, not to mention Special Teams.
Cincinnati have had 17 players go on IR this year, 4 so-called starters. The Defense was hardest hit with 11 of 33 originals, 2 starters. Add that 3 more are doubful today, 2 starters, and you have a Team with 7 starters and 19 of their original Defense, is it any wonder why they have been so bad. Another thing to remember is back-ups play together all Week in practice, problems only arise when injuries make practices futile.
There is a contention that injuries and starters out only impact significantly within that Week, the logic being, a Team have all Week to practice with the new player. So a case could be argued that The Eagles so-called back-ups will be better prepared this Week. Just some things to consider and happy New Year to all.