This is a continuation in how to effectively run the 3-4 defense. You can read about the base assignments in a 3-4 here, and how to run a Cover 2 out of it here.

The Cover 3 is probably the most popular coverage scheme at all levels of football. It provides a good balance of short and deep coverage. It’s called a Cover 3 because you have 3 players back deep to take away those long passes. You also have linebackers in the flats and over the middle. So the big weak spot in the cover 3 is that curl zone. 8-12 yards down the field on the side line is what the cover 3 gives up. Another weakness is covering seam routes by inside WR’s. It’s hard for the linebackers to get back far enough to defend seams, and if they have seams on both sides the safety over the middle has to make a decision.

With every defense you have to decide what you are willing to give up, and I think it’s pretty safe to say that the Cover 3 is overall one of the safest plays to call in most situations.

So let’s get to how to run it. Here’s a diagram of it:

34 Defense Cover 3


  • Cornerbacks (CB)- the cornerbacks should give the WR’s a cushion. I would have them line up at 7-8 yards off of the WR’s. On the snap of the ball they should start in a backpedal as they read the play, and as soon as they read pass they need to turn and run. They are responsible for a deep third of the field. The corners have to cover from the hash marks to the sideline on their side of the field. Their #1 job is to not let any receiver behind them. They are not responsible for any short passes. They are trying to prevent big plays down the field. You have to emphasize to them on a daily basis that they are not responsible for short passes, because the moment they try to jump a curl route is the moment the ball goes over there head for a touchdown.
  • Free Safety (FS)- the FS is responsible for the deep middle third of the field. They have to cover all of the ground in between the hash marks. They should immediately get into a backpedal on the snap of the ball looking for receivers coming deep. It is also very important that they do not get sucked up field on a short route. They can not try to jump slants or digs. The primary route they’re looking for is post routes.
  • Strong Safety (SS)- On the diagram here, I have the Strong Safety covering an intermediate middle zone but that is not the only option for him. You can have him play the curl zone on his side of the field if you want. But here I have him playing for a dig route from either side. His goal is to get about 10 yards off the LOS in the middle of the field and he can look for digs or slants coming from either side.
  • Inside Line Backers (ILB)- The ILB’s are responsible for slants while also looking for screens and draws. Once they read pass, they should drop back at a 45 degree angle to get to about 7-8 yards off the LOS. They should then look for anything coming over the middle.
  • Outside Line Backers (OLB)- The OLB’s are responsible for the flats. After they’re initial read step when they read pass they need to open their hips and run towards the sideline at about a 30 degree angle. They need to try to get 5 or 6 yards from the LOS towards the sideline. They have to get outside fast to cover out routes or short hitches. If they are too slow getting out there then you will have a lot of passes completed against you.

Now I want to go over probably one of the biggest threats to the Cover 3, and that is 4 seam routes. Obviously, when you have 3 people deep it’s pretty hard to cover 4 deep routes. But let’s look at how we can try to defend it.

34 Defense 4 Seam Routes

So there’s two big things I want you to see. First, it is absolutely necessary that the corners and safety are over the top of the WR’s. If they are running side by side with the receivers they stand no chance of covering all four routes. Being over the top is especially important for the safety because it will allow him to break on either inside seam route.

The second thing I want you to see is that the corners are not running straight up the field in the path of the outside WR’s, they are going slightly inside. Slightly is the key word, if they drift too far inside it’s an easy touchdown to the outside receiver. The purpose of them staying a little inside of the outside receiver is so they can help squeeze down the passing window to the inside seam routes. Remember, the corners have no help on the outside seam routes so that is their primary responsibility. Their only goal concerning the inside seam routes is to make it a harder throw for the quarterback.

At the end of the day, no matter what you do, it is going to be hard to cover 4 seam routes on a regular basis out of a Cover 3. So that safety over the middle has to make those inside receivers pay if they do catch a seam route. He can’t cover both receivers but he can make them fear catching the ball.

In conclusion, the Cover 3 is a pretty safe bet in most situations. It is a good base coverage and once your secondary gets it down it can be very, very effective. Just ask the Seattle Seahawks. The Legion of Boom is founded on the Cover 3.