Playing Sound Defense

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[edit] An Overview of a Sound Defense

  1. Always consider the # of coverage assignments when preparing an output for any situation. Consistently putting safeties in coverage of WRs is a formula for disaster. By the same token, expecting a CB to effectively cover the TE play after play will keep the opponent's offense on the field for long stretches.
  2. Design a general concept of man or zone, pressure or not, aggressive or conservative and try to keep that theme throughout. You should always have change-up calls in your defense but these should be a supplement to, rather than a competitor of, the general scheme. Splitting the calls evenly across all possibilities is not likely to afford you any real insight gained from observing performance.
  3. Once a general scheme is in place, compare your outputs to each upcoming opponent and adjust percentages downward on any call that doesn't fit well. It may even be necessary to remove some calls from the AI entirely if they would be easily exploited by the opponent.
  4. Continue to test out ideas and add outputs as the season wears on. Failure to do so could make your defense susceptible to good scouting. Scrambling the coverage is always a good idea. No matter how successful your scheme is, there will always exist a way to defeat it. Come playoff time, you don't want to be trotting out the exact same defense you have today.

[edit] Applying Pressure Effectively

There are several benefits to applying pressure effectively. It is much more than just producing sacks. However, the more you try to force it, the less effective it will be.

  1. In a 4-3 base, the blitzing of a single linebacker can lead to confusion in opponents' blocking assignments. If the LB is well adept as a blitzer, it can really add a lot. However, you cannot blitz the same LB (or same position) consistently and expect good results. In most cases the biggest advantage gained is in the confusion created, that is lost if the same player blitzes every time.
  2. In the 3-4, sending a single LB is not actually considered a blitz. The entire purpose behind the defense is to create indecision among the OLs because they don't know who the '4th DL' will be. Sending 2 can add even more confusion but also has the potential to leave areas of the field uncovered and exposed. And, as was the case with the 4-3, using identifiable patterns in whom you send will make it easier for a good offense/QB to exploit.
  3. Blitzing from Nickle, Dime, and Quarter sets, it is also possible to create a great deal of confusion. These can be especially difficult for the QB to read (when done well) because there are often many positions from which to bring an extra body. However, the decision on when to employ these blitzes is key. If you attempt this against a running play, it could spell disaster. If you send someone who has cover responsibility on the play it could as well.

Note: because of the call designs even sending one person in a 3-3-5, 3-2-6, or 3-1-7 is considered a blitz. Understand that there is always an exploit available to the offense any time you blitz.

  1. Sending multiple blitzers (except 2 from the 3-4) is considered extremely aggressive and should only be used in specific circumstances. It can be very effective as a run-blitz in short yardage situations but will almost inevitably leave the TE with room to roam freely. Any time you send multiple blitzers in a known passing situation, you are hoping the QB panics. If he remains composed, he will beat the blitz time and again.

[edit] Choosing a Base Defense

There are advantages to each defense.

The 4-3 is typically stronger against the power rushing game, but should be versatile enough to to handle any offense with fewer than 3 WRs.

The 3-4 is also capable of handling the rush as long as the offense runs a goodly amount toward the edges. And, contrary to popular belief, it does not offer any real advantage in WR coverage. It can be setup to be a little stronger against the pass to the TE and RB/FB, but that is about it. The 3-4 is versatile as well but, if put in the wrong situation, can be more easily exploited.

Whichever base you choose, try to remain open to the advantages the other affords. A good scheme can find a way to utilize both and still remain committed to its base.

[edit] Choosing a Coverage Shell

Cover 0 is the most aggressive option and should NEVER be combined with a zone. In Cover 0 once a receiver gets behind the defender their is no one to help. If he catches the pass it could be an easy score. Unless you are desperate, Cover 0 should only be used when you're backed up to your own goal line.

Blitzing: Blitzing is essential when using Cover 0. If you do not reach/panic the QB or stuff the RB, it will often lead to bad results.

Cover 1, often called Man Free, is a fairly aggressive shell and can allow a team to apply more pressure without abandoning cover responsibility. This shell can be combined with zone coverage underneath but it would still be somewhat susceptible to the deep pass. Typically Man Free, as the name would suggest, is a man coverage scheme. In order to use this as your staple, you should be able to create pressure and have faith in your CBs in coverage.

Blitzing: NEVER blitz your FS from a Cover 1 shell.

Cover 2 is a very versatile coverage shell. It can offer a good option for either zone coverage or man coverage underneath. When used with short coverage distances this shell can effectively allow for pressure and keep the TE seam route in check. As you increase the coverage distance it will become less versatile and will evolve into more of a passing defense which can be susceptible to the run and passing across the short middle. This shell can be run in almost any situation, but will be less effective in the red zone.

Blitzing: Avoid blitzing the SS from the Cover 2.

Cover 3 is a passing shell specifically geared to stopping the WRs. It is very easily exploited by the TE and should not be used too often when the offense is on schedule (1st & 10, 2nd & less than 6, 3rd & less than 3). It can also have major problems against the outside rush since the CBs will be in a backpedal at the snap. I do not mean to say that the Cover 3 is a bad option but, if used in the wrong situation (or against the wrong offense), it can keep your defense on the field all day as the offense just picks ups chunks of yardage. You can run man or zone underneath this shell, but man will likely place your LBs in coverage on WRs and the zones will be comparatively large.

Blitzing: You can blitz the SS from Cover 3, but it shouldn't be done often. You should never blitz the FS, CB1, or CB2 from this shell.

Cover 4 is basically just a prevent shell. It offers no real options to accomplish anything else. The more often you run a Cover 4, the more yardage you will give up-- regardless of the offensive scheme. The only time you should employ this shell is when holding a late lead or near the end of quarter 2.

Blitzing: There is no advantage to be gained by blitzing from a Cover 4. At its best there will be plenty of openings for the QB to find. Blitzing will not provide any confusion on his part. Even against the run. blitzing is not advisable.

[edit] Some other notes on Coverage Shells:

The Cover 0, 1, and 2 can be run from any set (other than GL).

The Cover 3 should have at least 3 CBs on the field. Otherwise you will have a LB assigned to WR1 or WR2 in either man or zone responsibility. It is designed for use with the Dime set.

The Cover 4 should only be used with Dime or Quarter sets. It is designed for use in Quarter sets.

[edit] LB Shifts

Shifting LBs can add two advantages. It can place a LB over the top of a strong TE to apply press coverage on the LOS. It can put LBs in space and make blitz paths more direct.

The problems with LB Shifts are several. It can tip the offense to what you are attempting to do. It can place your LBs out of position when an offense goes the other way-- this may be the result of a pre-snap read. It can make your LBs more vulnerable to O-line blocks.

It may be a good idea to use LB Shifts for variety while defending bland situations, but you do not want to use the shift in a way that tips your hand. If using shifts, try to mix them up as much as possible in those bland situations. That way, when there is a specific reason for the shift, the QB is not automatically alerted to what you are doing. If you are in doubt as to how best to use LB Shifts, it is best not to use them.

[edit] Play Focus

Play focus only changes the distance the LBs play away from the line of scrimmage. What happens after the play starts is determined by individual tactics and coverage settings (man to man/zone).

[edit] Which Nickel to Use? Which Dime to Use?

While the base defense is usually the determining factor when deciding whether to utilize the 4-2-5 or 3-3-5, it need not be the case in GLB. Look at the situation you are in. What weapons will the offense have at their disposal? Which would do the most damage?

Since we are talking about Nickel & Dime here, we'll assume that we are considering pass options as the bigger threat. So which would be better against a TE as the primary threat? The SS in coverage or a LB? Which would provide the best defense against a WR threat? Four DLs rushing or three?

While some will say those decisions are easy, they really depend on your personnel. If your LBs suck in coverage, you may choose the 4-2-5 against the TE. If your pass rush is more elusive and better in space, you may be better off allowing 3 of them try and outmaneuver 5 OLs than putting 4 into the standard set. The only way to know is to see your defense perform.

In conclusion, I'm of the opinion that you cannot have too many inputs or outputs. As you watch how your defense performs the calls you have, you will always find ways you can improve. You certainly will never use 100+ calls in a game, but you will find situations over the course of 16 games and the playoffs that could have been best defended by even more different calls than that. It's all about study; improving on what works; discarding of what doesn't.

[edit] External Links

Defensive Concepts, help with AI by Satchmo-n-Dizzy

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