Statistic that may surprise you: the San Francisco 49ers boast one of the top defenses in the NFL, currently ranked seventh in yards allowed (306.3 per game) and in points (17.3 points per game). Of course, two of their first three opponents this season have been the offensively challenged Seahawks and Bengals, so we'll soon find out whether or not they are for real.
ILB Patrick Willis
Any conversation about the Niners defense begins and ends with Willis. It's a cliche thing to say, but he is the heart and soul of this unit, and everything they want to do revolves around #52. At 6-1, 240, he is one of the most active linebackers in the NFL, whether it's stopping rushers cold, covering tight ends, or rushing passers. A Pro Bowler in each of his first four seasons, and a first team All-Pro selection in three of those, there's really only one way to get around having Willis in the ball carrier's facemask, and that's by going over the top -- not that you couldn't see him 50 yards downfield.
ILB NaVorro Bowman
An underrated piece of the league's third-best run defense (62.7 yards per game), the Penn State product takes over Takeo Spikes' spot as a run-stuffing inside backer. He's impressed so far in his first season as a starter, racking up 30 tackles through three games. If the Eagles commit to a ground attack again on Sunday, Bowman will have another productive game, because...
NT Isaac Sopoaga
It was widely assumed Aubrayo Franklin moving on to New Orleans would be a huge loss for this defense, but so far Sopoaga has filled his role just fine. Sopoaga has played in different spots along the 49er line during his seven-year career, but mostly at left defensive end prior to this season. Right now, he's proving his 6-2, 321 lbs. frame can draw and fight the double teams that give Willis and Bowman the lanes to be aggressive and attack the line of scrimmage. Needless to say, the interior of an offensive line that struggled to get push in short yardage situations against the Giants front last week will have their hands full on Sunday.
RDE Justin Smith
One of the most consistent defenders on San Francisco's D, Smith came over as a free agent from the Bengals in 2008. He's put up at least six sacks in each of his first three seasons there, plus he's a solid two-way player who has earned Pro Bowl recognition in back-to-back seasons. He'll be working on Jason Peters' side, and while usually we talk about how that impacts the game in pass protection, this week it will be interesting to see if Peters gets to those second-level blocks while he fights off the tenacious Smith.
OLBs Ahmad Brooks and Parys Haralson
So where do the Eagles attack this offense? Thankfully, the 49ers become much more pedestrian along the edges. First, the defense lacks the great edge pass rushers such as DeMarcus Ware or Clay Matthews that really make these 3-4 defenses go. Brooks and Haralson have both had their moments -- Brooks has 11 sacks over the past two years as a situational player, while Haralson once reached eight QB takedowns for a season -- but neither of them are somebody that requires extra attention.
CB Carlos Rogers
An old friend of the Eagles, we last saw Rogers in a Redskins uniform, as they were getting torched 59-28 in the middle of their comical 2010 season. A first round pick of Washington in 2005, he's been steady enough to hold a starting job from year to year, but is merely average. His interception last week was only the ninth in his career, so he's generally not a playmaker, nor is he somebody who is going to shut down premier wide receivers.
CB Tarell Brown, SS Donte Whitner, and FS Dashon Goldson
The rest of the defensive backs are a largely faceless mish-mash. Brown is the other starting cornerback by default, Whitner is dealing with a hip injury, and we're not really sure about Goldson, who had a big-play laden 2009, but was around the ball significantly less in 2010.
Clearly the way to attack this defense is through the air, but the Eagles' passing attack has looked inefficient during the first three weeks. There needs to be more focus from the receiving corps, and Michael Vick is going to have to suck it up and play through immense pain, because the numbers suggest they won't be able to lean on Shady McCoy this week.