For the last decade Eugene, Oregon, has been known mostly for its role in forming offensive storm systems that have indiscriminately brutalized Western U.S. college towns from late-summer through the early-winter. Lost in the hail of spread-option run attacks and plug'n'play prolific Duck quarterbacks has been the Oregon defense, which has recently asserted itself amongst the nation's elite.

In the last four years, Nick Aliotti's defenses have the following ratings in the Defensive F/+ rankings: No. 4 in 2012, No. 12 in 2011, No. 6 in 2010, and No. 22 in 2009, the year in which they began to install a new system.

That new system has its roots in the NFL from minds like Dick Lebeau and the Ryan family. It is the modernized take on the old 46 defense of Ditka's Bears. Now, the Ducks run multiple defensive fronts, and today's 46 proponents typically use more in their schemes than the basic front utilized by the 80's Bears. But it's still a good starting point to discuss the Duck's strategem.

The basis of the 46 "Bear front" is about outnumbering and attacking the offense at the point of attack. The main means of doing so is the way in which the linemen are arrayed.





Here you see a tighter version of the alignment. Often Oregon would line up with a zero tech across from the center, a 3-tech, and then a 4-tech across the face of an offensive tackle. The goal is to cover up the interior gaps with the line, clog the middle of the field, and free linebackers to flow outside.

Playing big 3-4 personnel is crucial for the Ducks in offering multiplicity and protection to what they want to achieve up front. The likely starters for the 2013 Ducks at these three positions will go 6'6 and 280 pounds, 6'3 and 295, and 6'6 and 292 at these three positions.

The Ducks will move these three big, athletic linemen around to create all kinds of different fronts with which to attack the offense's protections and blocking schemes. They start with a basic approach:





Here they are in the looser Bear front with DL across each of Kansas State's interior linemen. They attempt to 2-gap while the outside linebackers handle the role of forcing the runner back inside to the inside linebackers and linemen. In this instance, KSU successfully reaches the line, and the weakside backer is unable to stay outside of fullback Braden Wilson or the runner. Wilson levels two Duck defenders to lead to a big finish for the play.

From the 2-gap, three-man rush defense, which potentially puts eight defenders in coverage, the Ducks then have a variety of single-gap zone-blitzes that comprise the rest of their base defense.

Here they bring an inside linebacker into an interior gap while slanting the line fortuitously in the direction of the run. KSU's blocks are totally disrupted, and the gains from previous runs are negated. The Ducks' variety of zone blitzes include four-man rushes that bring a linebacker, as well as five-man Fire Zones. The Ducks include Fire Zones frequently for the way in which they mitigate risk with the 3-deep defender structure while firing blitzers into the backfield.

While the Ducks will use the 46 front, Under front, Over, and other strange combinations that sometimes involve the nose tackle standing up as a linebacker before charging the line, it all remains relatively simple for the linemen. Either they're slanting or twisting as a part of a zone blitz and looking to beat OL into the backfield, or they are aggressively attacking OL straight-up in 2-gap technique.

That paints a confusing picture for the opposing offensive line and creates a good deal of risk in avoiding negative plays against the run.

The challenges for zone blitzes usually involve asking linemen to play coverage and asking linebackers to fulfill a diverse workload. The 3-4 personnel is a better fit for zone-blitzes for that reason -- the three linemen are very rarely ever asked to play in coverage. However, as with the Pittsburgh Steelers, the multiplicity of the defense puts a lot on the linebackers.

Again, the nature of the 3-4 personnel helps in the types of athletes the Ducks can put on the field at these positions. The 2012 linebacker corps consisted of Dion Jordan (6'6, 247) and Boseko Lokombo (6'3, 233) and inside linebacker Kiko Alonso (6'4, 242) and Michael Clay (5'11, 222). Having an extra 220-240 pound athlete on the field results in having a lot of coverage and blitzing flexibility regarding which players drop into coverage and which players attempt to terrorize the QB.

Unfortunately for the 2013 unit, three of those players move on to the NFL. This is particularly challenging at the inside linebacker spot, which produced the Ducks' two leading tacklers in 2012, Clay and Alonso.

The base structure of the defense funnels runners inside where the inside linebackers can pursue them. Plus, the ILBs frequently blitz (Clay and Alonso combined for 24 TFL's and four sacks in 2012), and the nature of the coverages funnels receivers inside as well.

Both in the basic four-man zone blitzes and the Fire Zones, the Ducks employ Lebeau's seam technique to funnel receivers to the inside. This protects the deep safety and allows him to remain between the hashes while forcing the QB to make dangerous throws over the middle against the inside backers and the defensive backs:





The Ducks often lined up Clay and Alonso fairly deep in the backfield to give them time and room to play downhill rather than having to backpedal and then change directions in response to throws.

Nevertheless, finding inside linebackers who can provide the exceptional blitzing, tackling, and middle-of-the-field coverage of Clay and Alonso will likely be the deciding factor in whether Oregon manages another top-five defensive finish or drops back to the teens as in 2011 or 2009. Texas fans who witnessed the similarly Fire Zone-focused Longhorns attempt to replace Manny Acho and Keenan Robinson in 2012 can testify to the difficulties that can arrive in replacing the position.

Finally, there's the Duck secondary, which ties the entire system together.

Due to the nature of the zone blitzes, which define much of the Duck approach, the fronts and coverages are tied together for Oregon as defensive backs often have to replace run-support roles supplied by outside linebackers who are transformed into pass-rushing defensive ends on multiple snaps per game.

Aliotti brings a tremendous amount of disguise on the back end. The unit uses frequent movements and dropping to alter coverage looks right before the snap and prevent the quarterback and offense from noticing and exploiting vulnerabilities in the coverage.

At the heart of all the coverages, however, is the middle-of-field-closed (MOFC) structure of Cover-3 or Cover-1. The Ducks play both coverages, but in Cover-1 they rarely play press coverage on removed receivers unless they are in the red zone with the end zone at their backs. Oregon also employs pattern-matching to blend the philosophies of Cover-1 and Cover-3. Their base three-man rush with 2-gap technique plays three deep, 6 under; the normal zone blitzes drop three deep and four under; and the Fire Zones usually drop three deep and three under.





On this play against Kansas State, Oregon shows a tight cover-1 look before the snap. Then the deep safety and field corner bail to deep positions to prevent big plays. The field corner, Ifo Ekpre-Olomu, manages to reach the short throw, when Collin Klein brings his eyes to his side of the field.

The coverage is a Cover-3 Sky call, in which the deep thirds of the field are defended by the boundary safety (deep middle) and the cornerbacks. The "Sky" designation indicates that the run force responsibility goes to a safety. The field safety here covers the curl route and then the flat, based on the QB's eyes. On a run play, he's to force the ball inside.

The Ducks would play variations of Cover-3 and also mix in occasional shots of Cover-2:

And Cover-3 Cloud, with the "Cloud" tag designating that a corner has run force responsibility.

The advantage to this coverage is that the deep defenders begin with deep alignments, and Ekpre-Olomu often serves in each defense as more of a safety than a corner. He's solid in coverage, but the real key to the Ducks' ability to generate turnovers and prevent big plays is the deep alignment of their secondary and inside linebackers and the way they play the ball and tackle in the open field.

Every once in a while zone-blitzes will place a defensive front in a vulnerable position and open up creases for runners, in these instances it's essential that the deep three defenders are good open field tacklers to minimize the risk.

In the roll coverage above, the boundary safety starts from a deep position on the half and covers a deep 1/3 of the field. The field safety drops straight back and Ekpre-Olomu has already dropped back to join them before the snap.

By the time the ball is snapped, none of them are closer than 10 yards from the line of scrimmage. By employing 3-deep coverages with soft cushions, Oregon allows its secondary to play mostly downhill against both the run and the pass. By utilizing mostly MOFC coverages with a small smattering of Cover-2 zone, they keep the coverage principles fairly simple.

These MOFC coverages allow Aliotti to outnumber the run with eight-man fronts, further bolstered by the Oregon 46 technique and zone-blitz heavy approach. The resulting picture for an offense to decipher is a constantly shifting, moving defense that frequently puts people into the backfield and is very difficult to beat over the top. There are openings in the flats and possibilities downfield if the offense catches a deep defender out of position. But the former are swallowed by the Ducks' speed, and the latter are rarely available due to the pass rush.

Matt Barkley and the USC Trojans were the one offense that was able to attack the Ducks successfully. This was largely a result of Barkley's advanced football acumen, tremendous footwork under pressure (he still threw two picks), and the Trojans' ability to field multiple excellent receivers to attack the soft parts of the Oregon zone coverages. Of course, the Oregon offense outscored the Trojans with a 62-point day on offense.

With the modern 46 zone-blitz playbook, the Ducks have an aggressive philosophy on defense, much like on offense. It is geared towards overwhelming opponents at the line of scrimmage while backing up the line with deeply aligned inside linebackers and defensive backs. The fact that they can present all kinds of fronts and varieties on their basic defenses without teaching a lot of different techniques allows them to field an exceptionally fast, hard-hitting defense without the recruiting rankings of a traditional power or SEC program.

Given what they return on offense, if the Ducks can fill in the missing pieces at inside linebacker, they have to be considered amongst the frontrunners for the 2013 MNC hunt.