Once that offense starts clicking, the defense can't help but to improve. I'm personally not all that worried. I think Philly has a good chance to be one of the teams to beat in the NFC this year. They have a lot of talent on both sides of the ball, they are just dealing with some injuries and adversity earlier than most of the teams in the league. Bradley gone, Cole and Westbrook have been out, losing the DC, etc. Give it some time and I think you see some big time improvement.
Preseason game 3 is when it gets serious. If they flop in that game I start to get a little worried.