This post will attempt to explain basic 4-3 fundamentals, the Tampa 2 scheme, and how our linebacking corps might shake up.
The most obvious assertion here is that there are four down linemen, three linebackers, and four defensive backs.
You will commonly hear 4-3 linebackers referred to as Sam, Mike, and Will linebackers.
Sam refers to the Strong side Linebacker, (Madden's LOLB)
Mike refers to the Middle Linebacker, not a 'Mo' Linebacker (Thats in a 3-4)
Will refers to the Weak Side Linebacker (Madden's ROLB)
In a 4-3 the Strong side of the defense is the side with the primary TE or the overloaded blocker side. In a spread formation with no TEs or FBs, the side with more personnel would technically be considered the strong side even though it would most likely be referred to by the receiver formations. In Madden the ROLB is considered the Will Linebacker because teams typically run to the right (defense's left), making the right the de facto Will linebacker role.
The Sam Linebacker has varying responsibilities. Depending on the Coordinators scheme, the linebacker will be responsible for securing the edge (i.e. keeping containment). Other responsibilities include covering the TE in passing situations in a man coverage scheme. In a zone scheme Sam Linebackers typically fall into a curl zone that encompasses intermediate routes to the TE. Sam Linebackers are typically expected to be physical and capable of shedding blocks. These defenders are necessary against effective running teams. The Sam Linebacker is typically nothing more than a role player because they are typically just 2 down players at best and get off the field in Nickel situations.
The Middle Linebacker is typically the most pure linebacker of the trio. The Middle Linebacker usually assumes pre-play responsibilities of calling audibles, line shifts, etc. The Middle linebacker in a 4-3 typically plays a hook zone in the over the middle of the field, unless in a Tampa 2 to be described later.
The Will Linebacker usually has no TE in front of them. They should be athletic and great tacklers, especially in a Tampa 2. Defensive coordinators will typically scheme to direct running players towards the Will Linebacker.
When describing a scheme, the typical jargon will surround the coverage. Cover 1, Cover 2, Cover 3, Cover 4, etc.
The type of cover refers to the amount of defenders dropping back into deep coverage.
Cover 1 refers to a Free Safety providing the insurance policy against deep routes. This is why Free Safeties have to have a quick change of direction to cover a lot of ground. Cover 1 is typically used in some sort of man formation or aggressive blitz package.
Cover 2 typically refers to having two safeties playing deep zones. There are variations.
Cover 3 will typically refer to one safety dropping back over the middle, with the two outside corners dropping back deep. The zones are equal areas of responsibilities. This is changed in a Tampa 2 by having the MLB cover the deep middle instead of the safety.
Cover 4 is four deep defenders (Edit: credit to weepingbear for the clarification)
There is a Cover 6 defense, but it is typically used in 3-4 systems and just denotes three deep defenders with unequal areas of responsibilities.
Cover 7 is a variant of Cover 1
(Cover 0 is strict man to man)
Prevent as described in Wikipedia (shameless, I know):
Prevent defense is an American football defensive alignment that uses seven or more defensive backs or players in a defensive back role, the goal of which is to prevent the opposing offense from completing a long pass. This defense is frequently used in obvious passing situations, such as a third-and-very-long situation, or to prevent a long score on the last play of a half, or when the defense believes that the offense must pass (for example, if the offense is trailing late in a game). Otherwise the prevent is almost never used. The defense trades size for speed, and tries to ensure that no receiver can get behind the defense. A prevent defense backs up the coverage so far that it will often give up long yardage, but it makes scoring a touchdown in a single play very difficult.
Credit: SMD for not letting me play fast and loose with the word "Prevent."
The most typical form of a Prevent defense shown below:
Why everyone facepalms when you make a stupid assertion such as McClellin to LB and Hardin to LB
Where are you putting these players? McClellin is weak in coverage, are you going to line him up over a TE and hope opposing offenses don't gameplan for that weakness? He is physical enough against the run to be an effective 4-3 Sambacker, but as soon as that TE runs a route, he's screwed. If you want to develop the defense into an Attacking 4-3 concept similar to NYG and DEN, that's a different conversation. The issue with this is that you are theoretically changing what has brought this defense success in the past. In order to have your Sambacker constantly blitz, another defender has to take his coverage scheme. Either the safety comes up and plays a curl zone or the linebackers take bigger areas of responsibilities. The Mike backer in these cases can't play the deep/middle third of the field and the Tampa 2 concept is conceptually busted because the defense is effectively playing a classic cover 1/cover 2 concept. This is fine, but it exposes you to big plays. (i.e. Jacoby Jones ala the AFC Division Championship game) Any time you need more than four players to rush the passer, you open up holes in a zone system.
Hardin, is not big enough to be a consistent Sambacker, period. I don't care what Bleacher Report has to say, or what Rosenbloom or any other hack tries to deceive you into thinking. He wouldn't be physical enough to get off blocks and secure the edge. He would do good in coverage.
Hardin's value will most likely be as a nickel corner in some sets, if he doesn't start at Safety. This would be more effective against certain offensive looks. If the offense lines up in a spread offense, Hardin would be very useful as the fifth or sixth defensive-back.
Our new acquisitions at Linebacker
DJ Williams (6'1" 242) has ample speed and will probably be used as the MLB in a Tampa 2 scheme or any 4-3 set we adapt. The pick up is exciting. He was a candidate for DROY in 2004, when the award went to Vilma. He played WLB in his rookie year. His sophomore year he moved to SLB, he also had a DUI this year. In 2007-08 DJ moved to MLB due to an injury to Al Wilson. That year he finished 2nd in tackles in the NFL, 1st in the AFL. If you want an attacking 4-3, this pick up should bolster your claim. DJ can play any position in our linebacking corps as long as he learns to use Uber instead of driving home after the club.
Mel Tucker - There have been a few articles on here that have looked into Mel's possible schemes. I don't think Mel is married to any specific philosophy as he's been active in both a 4-3 and 3-4 scheme. The only interesting note that I can make is that the Linebacking corps that he coached in Jacksonville seemed to rely more on attacking and shedding blocks than our Linebackers last year. A player like Daryl Smith seems more reminiscent of James Anderson than Roach.
If I missed anything important please clarify and I'll repost. I understand not everyone will agree with my conclusions, especially since this blog has quite a few Roach fans.