USC Trojans

LOS ANGELES -- There are many different defensive fronts the Trojans offense faces throughout the season, but there few that consistently see on a weekly basis. With a lot of last season’s success in the air coming from what the offense was able to do on the ground, we take a look now at what the front seven sees from week to week.

4-3


The 4-3 defense is the most commonly used defense on every level of football. It starts with the nose tackle, who will line up shading to the left or right of the center depending on the strength of the offense. The defensive tackle will always line up on the outside shade of the guard and his alignment on either the left or right guard is based on which side the strength of the offense is called. If there isn’t a stunt or blitz called, then the nose would be responsible for the A-gap that he is shaded too in between the center and guard and the tackle would be responsible for the B-gap that he is lined up in. The defensive ends are lined up in a tight or wide 9-technique over the tackle or tight end. Their jobs are to contain the edges of the line of scrimmage against the run while racing up to try and sack the quarterback in passing situations.

With the zone blocking scheme that USC runs, going up against a 4-3 defense allows for bigger plays in the run game. The zone scheme allows offensive lineman to not focus on a particular man but rather an area. With the zone, usually one lineman will be working with another lineman to his left or right and the two will block whoever is in their assigned area. On the backside of wide zone running plays, the backside tackle or guard is assigned to cut the man on his inside. With the four big bodied players on the line of scrimmage who want to penetrate up field to stop the running back or quarterback in the backfield, their eagerness to rush up field makes it easier for the backside to be cut, leading to bigger gains as a result.

3-4


The 3-4 defense is becoming more and more popular throughout football. In this front the nose tackle is lined head up over the center rather than in a shade and two defensive tackles are lined head up over the offensive tackles as well. The job of the defensive linemen in this formation is not so much to penetrate up field but rather to disrupt the blocking of the offensive line by playing through them and playing the gap to the left and right of either the center or tackle. With that being said, in the 3-4 front every gap on the line is the responsibility of the defensive linemen. With this concept, it gives the green light for the four linebackers to run around the field and be more aggressive.

This defense it makes it more difficult for the offensive line to get a good push at the line of scrimmage. With the center and the two tackles’ defenders heads up on them playing the two gap, it makes it very difficult to get leverage with the zone. Another wrinkle that the formation takes away from the zone blocking offense is the ability to not be able to cut on the backside. With the D-linemen responsible for both gaps instead of one, they’re slower off the ball, thus not creating enough momentum for the offensive line to cut them on the ground. A lot of offenses tend to run the ball outside and away from the middle of the defense, but sometimes the best way to gain yards on the ground against the 3-4 is to attack it by running power, traps, and sometimes draws up the middle.

Bear

The bear front is more of a pre -nap adjustment or a secondary front that teams will complement the 3-4 or 4-3 with. In a pre-snap adjustment, the defensive end on either the strong or weak side will steam down to a 3-technique before the ball is snapped. The shaded nose tackle will line head up on the center, and either the SAM or WILL linebacker will line up on the line of scrimmage taking the place of the defensive end that steamed down to the 3-technique.

The bear front is used more to stop the run and to try and eliminate any double teams by the offensive line. If need be, most offenses can handle the adjustment of the different blocking assignments before the snap of the ball, but because there are now eight defenders in the box, it leaves at least one one-on-one matchup on the outside. If the quarterback can recognize this early enough and change the play, then he can call a play to get a first down, if not more.

In this episode of RecruitingNation 411, we focus on the offensive side of the ball in the 2013 recruiting class. Our experts tell you which prospects are primed to be the stars of the 2013 class, and which ones have already given a verbal commitment.

The USC Trojans were a young team in 2011, but several upperclassmen made their marks on a 10-2 season and will now have an opportunity to do it again at the NFL Scouting Combine.

Seven draft-eligible former Trojans will take part in the event, which begins Feb. 22 in Indianapolis.

The players are offensive tackle Matt Kalil, defensive end Nick Perry, tailback Marc Tyler, tight end/fullback Rhett Ellison, linebacker Chris Galippo and defensive tackles DaJohn Harris and Christian Tupou.

The events each player will participate in at the combine is yet to be determined, as some may wait to take part in events -- such as the 40-yard dash or three-cone drill -- at USC's Pro Day, which is scheduled for March 7.

We like doing Power Rankings at ESPN.com. These are the post-signing day Power Rankings.

If you want to see where your team stood on Jan. 10, go here.

The schedule does not factor into these. This is a projected pecking order based on where a team stands right now.

And if you don't like where your team is in the post-signing day Power Rankings, then I'd suggest whining about it until your team plays better.

1. USC: The Trojans ranked 13th in the final recruiting rankings with just 12 signees. They will be ranked in the preseason top 5, perhaps even No. 1. If things go according to plan, USC will blow a big raspberry at Paul Dee next January.

2. Oregon: The Ducks surprisingly lost QB Darron Thomas to the NFL, but the far more important news is not losing coach Chip Kelly to the Tampa Bay Buccaneers. A strong recruiting class and another likely top-5 preseason rankings sets the Ducks up nicely to enter the national title chase.

3. Stanford: Stanford signed the best recruiting class in the Pac-12. It was ranked 12th by ESPN Recruiting and much higher by just about every other recruiting service. While the Cardinal have big holes to fill -- most notably behind center -- a glance through the roster suggests those rooting for the program to topple after a grand rise are going to be disappointed.

4. Washington: Much of the recruiting season had been disappointing for the Huskies, particularly losing almost all of the top in-state prospects, including a pair of A-list linemen who would have addressed major needs. But Steve Sarkisian made a series of aggressive moves rebuilding his coaching staff, most notably with the hiring of defensive coordinator Justin Wilcox and ace recruiter Tosh Lupoi. That supplies much of the positive momentum here.

5. Utah: The Utes signed a strong recruiting class and welcome back a wealth of starters from a team that won eight games without much production at QB. The promotion of 24-year-old Brian Johnson to offensive coordinator was a surprising move, particularly with fans rooting for a "celebrity" hire. It could prove to be a stroke of genius, but the onus is now on Johnson to make it become so.

6. UCLA: The Bruins are the big climbers from our Jan. 10 power rankings -- moving up from No. 10 -- but that's what happens when new coach Jim Mora punches back at skepticism with an outstanding recruiting class. A team that looked like a "neh" is moving closer to a "maybe."

7. California: Despite all the hand-wringing over the loss of Lupoi and receivers coach Eric Kiesau to Washington, the Bears still signed a top-25 recruiting class that addresses needs. Still, perception matters, and at present, Bears fans seem more worried than optimistic. Nothing, of course, a few wins in a shiny remodeled stadium can't change.

8. Arizona: Rich Rodriguez's recruiting class finished at or near the bottom of the Pac-12, according to most rankings. That said, Rodriguez got his man at defensive coordinator, Jeff Casteel, which is significant because most trace the problems at Michigan to his failure to do so for the Wolverines.

9. Washington State: The Cougars didn't soar in the recruiting rankings just because of the hiring of coach Mike Leach. Still, that doesn't appear to be dampening the enthusiasm in Pullman.

10. Arizona State: New coach Todd Graham did a solid job salvaging the Sun Devils' recruiting class. But the loss of QB Brock Osweiler to the NFL and the NCAA's rejection of receiver T.J. Simpson's bid for a sixth year of eligibility leave the program with plenty of questions on offense. And just as many on defense.

11. Oregon State: The Beavers were victimized by a handful of late recruiting flips that put dents in what was shaping up to be a strong class. And the loss of secondary coach Keith Heyward to Washington also was a blow. On the plus side, the Beavers will see 17 returning starters during spring practices.

12. Colorado: The Buffaloes remain at the bottom because the bottom line is this: They welcome back 13 starters from a team that went 3-10 and ranked last in both scoring offense and scoring defense. Still, coach Jon Embree put together a solid recruiting class, one that could become the foundation of his substantial rebuilding project.