Re-building the 2013 Eagles Defense

New Defensive Coordinator Billy Davis will be the architect of the re-vamped 2013 Eagles defense. Many fans are expecting a switch to a 3-4 defense, but Billy Davis runs a 4-3 under front. He hasn't publicly declared the Eagles a 3-4 or a 4-3 but I think it's safe to assume he'll run the 4-3 under he's ran in the past. The Seattle Seahawks are another team that  runs the 4-3 under front.

Let's take a look, position-by-position at what responsibilities each player will have in the 4-3 under defense.

Left Defensive End:
- In 2009, Billy Davis had Calais Campbell as his LDE. Campbell is 6'8" 282 lbs. In Seattle, this position is occupied by Red Bryant (6'4" 323 lbs). So this isn't the defensive end we're used to in Philadelphia (insert Jason Babin joke here). The LDE spot in the 4-3 under is more for a run-stopper than a pass-rusher. They're looking for a guy with 4-3 DT size.

Dorsey has been a bust in KC but could be a servicable
starting LDE in Philadelphia.

I don't think the Eagles have this guy on their roster right now. Fletcher Cox is an ideal fit for the Right Defensive Tackle spot. There are a few options in free agency:

- Jason Jones (6'5" 276 lbs) - He is more of a pass-rushing DT in a 4-3, but he's got decent size and would come at a discounted price. He also played in Seattle last year so he has experience in the 4-3 under front.

- Richard Seymour (6'6" 317 lbs) - He's got the size and experience. He's good at stopping the run and still has pass rushing skills. He is 33 years old but has at least two good years of football left. It wouldn't be cheap, but wouldn't be a long-term commitment either.

- Glenn Dorsey (6'1" 297 lbs) - He's got the perfect size for this role and he's a proven run-stuffer. He's known for being a big draft bust in Kansas City but he should come at a reasonable rate and he's still only 27 years old.

Left Defensive Tackle:
- This is the nose tackle. He'll line up between the guard and center. He's a big body that is very tough to move. This player will be double-teamed often and asked to occupy the center (freeing up a one-on-one for the RDE). The Eagles are used to having undersized defensive linemen, but this position will definitely break that mold under the new system.

The Eagles don't have a starting-caliber nose tackle on the roster. Antonio Dixon has the size, but would be a better fit for a very good backup NT. There are a couple options in free agency:

- Alan Branch (6'6" 325 lbs) - He was the starting LDT in Seattle last year. That makes him a potential hot target for Howie Roseman this offseason. He's got the size and experience in this system.

Fletcher Cox had a stellar rookie campaign for the Eagles

- Terrance Knighton (6'3" 330 lbs) - His nickname is "Pot-roast". He's a huge thumper in the middle. Knighton has flashed as an elite run-defender and he's also looked uninterested at times. He's still only 26 years old and has potential. For the right price, I think it's worth the gamble.


Right Defensive Tackle:
- This is where I expect Fletcher Cox to have a breakout season. Cox had an outstanding rookie campaign and has received comparisons to Richard Seymour. He should have a seamless transition into the RDT role. In the 4-3 under, the RDT will line up between the tackle and the guard. With the NT occupying the center and the Right Defensive End occupying the tackle, Cox will get many one-on-one pass rushing opportunities. Pete Carroll said the right defensive tackle spot is where you put your best interior pass rusher in the 4-3 under.

Right Defensive End:
- This is the "Predator" in Billy Davis' scheme. This is the pass-rush specialist. Chris Clemons fills this role in Seattle, Bertrand Berry (6'3" 270 lbs) filled this role for Billy Davis in Arizona. In 2009, Berry rushed the passer 94% of the time and dropped into coverage 6% of the time just to mix it up. I think this is a perfect role for Trent Cole. He's got the same size as Berry, and he's got the athleticism to drop into coverage 6% of the time. Jim Johnson used to put him in coverage on rare occasions, so it's not foreign to him. Brandon Graham fits this role as well, but Cole is just a better player. Graham could be a very nice backup, spelling Cole to keep him fresh.

Strong-side Linebacker (LOLB):
- In 2009, Chike Okeafor (6'5" 265 lbs) played this position for Davis. Okeafor rushed the passer 70% of the time and dropped into coverage 30% of the time. I don't think Brandon Graham or Vinny Curry have the athleticism for this role but I think there are many great draft prospects, I'll save that for a later post.

Anthony Spencer played a similar role in Dallas
and could have a big impact in Philly.

Let's look what free agency has to offer:

- Anthony Spencer (6'3" 250 lbs) - He's probably the only name I would get excited about in this free agent class. He had a very productive year in Dallas last season, and with their grim salary cap situation, they could let him hit the open market. He's still only 29 years old, so a 4-year deal seems reasonable. He's athletic enough to fill the SAM Linebacker spot in this system.

- Paul Kruger (6'4" 270 lbs) - He's only 27 years old and had a productive year in Baltimore last season. I'm not sure he has the athleticism for this role in pass coverage.

- Daryl Smith (6'2" 248 lbs) - He has major injury concerns, but he's been very productive in Jacksonville when he's on the field. He's good as a run-stopper and a productive pass-rusher. Not sure if he's got the ideal size Billy Davis is looking for, though.

Middle Linebacker:
- This is the thumper in the Billy Davis scheme. DeMeco Ryans wasn't great in Houston's 3-4 defense, but that was primarily due to his injury. He's healthy now and had a good first year in Philly. Gerald Hayes (6'1" 253 lbs) played this role for AZ in 2009. Ryans will play quarterback for this defense and should excel in this role.

Weak-side Linebacker:
- Mychal Kendricks will finally get to play a natural position that uses his strengths. The weak-side backer has a defensive lineman wall in front of him. This frees him to use his athleticism and make free runs to the ball-carrier and quarterback. Kendricks played out of position for most of last year but he played ILB in a 3-4 at California. I expect Kendricks to have a great year under Billy Davis in 2013.

Summary:
- This is an in-depth look at the 4-3 under front. It's different but Seattle proved last year that it can work and work very well with the right personnel. I think DeMeco Ryans, Mychal Kendricks, Fletcher Cox and Trent Cole will be the only front-seven starters for Billy Davis that are currently on the roster. I also think Brandon Graham, Antonio Dixon, and Cedric Thorton will play important roles as well.

- So the Eagles need a Left Defensive End, Nose Tackle, and a Strong-side Linebacker to complete their re-vamped front-seven. I will come out with a post later this week looking at some of the draft prospects that could fill these voids.

* Follow me on Twitter @Matt_Chastain25 and @eaglesalldayblog, I'll get ya back!