Michael Vick - This one is easy. For the Eagles its all going to start and end with how Vick plays. He won't be able to throw 4 picks against the Ravens and still have a shot to win at the end. I know he only took 12 snaps in the preseason and he may have been rusty last week, but that's not going to fly this time around. Vick and the Eagles offense played what amounts to a game and a half worth of snaps against Cleveland and Vick threw the ball 56 times. That's easily a preseason's worth of work right there. Season starts now.
Eagles run defense - This is the week we find out if its for real. The Eagles completely shut down the Browns' ground game, but that was a bad offensive line and rookie back that didn't play a snap in the preseason. With the Ravens, the Eagles will be facing one of the best backs in the league, Ray Rice, and an offense that has been run first for years. Baltimore's passing attack is also significantly better than the Cleveland's, but make no mistake about it... The Ravens want to run the ball and if they can't, it seriously disrupts their plans.
In games where Joe Flacco threw the ball less than 30 times last year, the Ravens were undefeated. In games where he threw the ball 30 or more times, they were just 6-5. Flacco had a QB rating of better than 100 6 times last season, 5 of which came in games where he threw less than 30 passes. The more you force the Ravens to throw, the worse they are.
Finally, everyone is very hyped on the Ravens after week 1, but what did we really learn about them? They got a big win at home against a team they swept last year. They scored 55 points in two games against the Bengals last season. That Cincy team did not beat a single team with a winning record last season.
This is not to say it wasn't a great performance and the Ravens aren't real contenders, but who didn't already think they were before week 1? The Ravens are who we thought they were. Its the Eagles we don't yet know about.