The Eagles' secondary can't keep getting shredded by opposing QBs.
Winning tends to allow us to gloss over team deficiencies. The problems begin when those same deficiencies begin leading to losses. The regular season opener versus the New England Patriots exposed a weakness in Philly's game. Those issues have grown into full-blown concerns. One of which is the frequency with which teams are embarrassing Philly's secondary.
Against the Patriots, the Eagles' defense allowed 316 passing yards and three touchdowns to quarterback Mac Jones. Minnesota Vikings gunslinger Kirk Cousins had his way with Philly's defense the following week. He racked up 364 yards and four touchdowns through the air.
While Philadelphia won both contests, the issues with defending the pass were major concerns. Entering Week 16, the Eagles ranked 29th in yards allowed (3,820) and 31st in passing TDs allowed (30). They ranked 29th in interceptions. They only have six of those.
Philly is surrendering too many pass yards. They allow too many touchdowns through the air. In short, the defense has been unreliable on passing downs. It's understandable why they have struggled to get off of the field on third down.
There are other reasons for fans to be concerned, but if the Birds don't turn this around quickly, the losing will continue regardless of who the opponent is.