After four preseason games, new defensive coordinator Billy Davis may be wondering just what he signed up for in coming to Philadelphia to shepherd a motley crew of castoffs and holdovers through a transition from an old scheme they didn't play well to a new one they might not fit.

Davis has already shown a willingness to compromise on his first-year plans, as we can see by looking at the pre-snap positioning of the defensive line. Davis opened the first preseason game in a traditional two-gap 3-4 front: nose tackle Isaac Sopoaga lined up directly over the center, while defensive ends Cedric Thornton and Fletcher Cox were heads up on the tackles.

Notice the three different stances of the linemen. On the left, Thornton is in a four-point stance, which helps him stay low and anchored against a powerful offensive linemen. Sopoaga is in a three-point stance with his heels down (shifting his center of gravity backwards) and slightly "flexed" off the line of scrimmage, looking to read the play and control blockers in the middle. Cox is in the classic three-point track stance on the right, ready to fire off the ball and rush outside after Trent Cole drops into coverage.

Against this alignment, the Patriots' starting offensive line easily controlled the line of scrimmage on the way to two early touchdowns. By the Carolina game, Davis had made his first concession to personnel, shifting Thornton inside to the "B" gap between the right guard and tackle:

Thornton is back to a three-point stance, less concerned in this position about being blown off the ball by a lineman outweighing him by 30 pounds.

On this particular play, Sopoaga is shaded a hair to his left, but his position changes frequently based on the play call. When he also shades to the right, the Eagles are basically in an "over" front, which is a neat little joke on all of us who spent the summer making a big deal about the 4-3 "under" look Davis frequently ran in Arizona.

On nickel downs, Davis mixes things up even more, taking Sopoaga off the field and calling for Cox and Thornton to switch sides:

With this switch, it's possible he's trying to increase the pressure he can get from a four-man rush by giving Cox a one-on-one matchup against the right guard, as Thornton tries to shoot the "A" gap on the other side. If this is actually the intent, it hasn't paid off so far, because Cox isn't winning those battles. If that keeps up, one has to think Vinny Curry will get a chance to show what he can do in that same setup.

Lacking pressure from the front four, Davis will turn to the blitz, where he's already demonstrated a Jim Johnson-esque flair for breaking protection schemes. The last 2 years of "send four and hope for the best" are definitely behind us:

In looking at that table, it appears Davis is blitzing his inside linebackers more and his safeties less than he did in Arizona. However, the scheme has actually changed less than the players. Whereas in Arizona, Davis frequently replaced a linebacker with a safety to give a "heavy dime" look, this preseason he stuck with the bigger guys:

After the Houston Texans switched to a 3-4, DeMeco Ryans was the linebacker-replaced-by-a-safety on passing downs. Ryans has to be happy that for now he's staying on the field, even if only because Davis has very few safeties he ever wants to play.

On the scheme side, here's a great example of a blitz Davis is running that breaks a protection scheme by bringing four rushers against three blockers:

At the snap, the right defensive tackle crashes the inside shoulder of the left guard (1), while the right defensive end races up-field (2). The running back steps forward to check for a blitz and fill the resulting rushing lane (3). Davis defeats this by bringing both linebackers on a blitz through the same gap (4), giving a two-on-one advantage. If the running back ignores the first blitzing linebacker and releases into a pass route, the second man breaks off his blitz and takes him in coverage.

This is a man-blitz concept, but with Davis coming out of the Dom Capers coaching tree, the guess is that we'll likely see a heavy dose of zone blitzing, with five rushers and six men in coverage. The challenge there is that the rebuilt defense has so far struggled when asked to play these types of zones.

Last week, I mentioned the issues Trent Cole was having with his pass drops, but the problems extend all the way to the back of the secondary:

This is the first Jaguars touchdown in Week 3, on the drive where the Eagles' defense made Chad Henne look like Drew Brees. On the right, the two outside receivers will run short crossing routes (1), while inside receiver Justin Blackmon will run a flag to the corner of the end zone (2). The Eagles are trying to disguise their coverage before the snap, but they're in cover three, which means Bradley Fletcher has to bail quickly off the line outside to cover the deep zone (3). Safety Patrick Chung is lined up in the middle of the formation, which seems out of position against a 1x3 set (4). Compounding that error, Blackmon is seven yards off the line of scrimmage before Chung even reacts to him (5), leaving him no chance to bail out Fletcher after the cornerback is late in his drop to the deep third.

Fletcher came to the Eagles with the reputation of being good in press-man coverage (when healthy), but less so when asked to operate in space. So far, we haven't seen much that would change that opinion.

Of course, as Paul Domowitch noted last week, these are the same types of breakdowns we saw out of last year's secondary as well. The holdovers aren't off the hook either:

In this play early in the Carolina game, DeMeco Ryans blitzes to become the fourth rusher as both outside linebackers drop into zones (1). It's again cover three and as the play develops, Panthers quarterback Cam Newton is clearly reading the two outside receivers to his right (2). As the slot receiver pushes up the seam, threatening both Fletcher and Chung (3), Nate Allen is late coming off him to play the outside receiver breaking back to Newton (4) for an easy completion.

At least Nnamdi wasn't involved.

(Derek can be reached on Twitter at @Igglesblog. His work can also be seen at