There's been a lot of talk about the Bear Raid, but so far no one's really talked about our defense. This post will serve as a quick introduction to our base front, and I'll talk about coverage in another post. Keep in mind that the looks our defense showed in the spring game were largely limited by the small number of formations and plays run by our offense, as well as by the fact that we're still at an early phase of installation (we'd only just installed a few blitzes before the spring game). At this point, we have a limited understanding of how the defense will adjust to play against pro-style teams and the like, and I'd imagine that we'll see more defensive line movement and a greater variety of blitzes and coverages in the fall. This post will give you a pretty cohesive view of our base defense, though, so you can be on the look-out for things that are different in the fall.

The Under Front
It looks like our base front is the “Under.” This is a solid front against most pro-style run games, and is pretty common throughout all levels of football. This was the front used by Pete Carroll at USC, for example. Perhaps less expected, our 3-4 under Clancy Pendergast was often aligned in an under, which is one reason you shouldn't worry about our switch to the 4-3. But more on that in a minute.

To understand what the under is and how it's different from other fronts, we need to talk about the numbering of defensive “techniques.” These aren't “techniques” like you're probably thinking about, but rather they just tell the defensive player where to line up relative to the offensive linemen. Even numbers tell the defender to line up heads-up over the offensive blocker. A defender playing heads-up over the center is a 0-tech, and the numbers get bigger as you work your way down the line. So, heads-up over the guard is a 2-tech, heads-up over the tackle is a 4-tech, and heads-up over a TE is a 6-tech. If you don't want the defender to line up heads-up over his blocker, you can shade him either inside or outside. Inside shades are designated with an “i.” So, a guy shaded inside a guard is a 2i, a guy shaded inside a tackle is a 4i, etc. Outside shades are odd numbers, so a guy shaded outside the center is a 1-tech, a guy shaded outside a guard is a 3-tech, etc. The TE numbering is a little different for no apparent reason, but that's not important. Here's a chart to help you visualize this:


This gets us to the under front, and will help clear up some of the positions listed on our depth chart. Against normal 21 personnel (two backs, one TE = 21 personnel), the SAM linebacker is going to line up in a 9-tech to the TE side of the formation. Our SAM backers are Jalen Jefferson and Michael Barton. The defensive end lines up in a 5-tech to the same side. These guys are Brennan Scarlett and Todd Barr. The nose tackle lines up in a 1-tech to the TE side. Our NT's are Deandre Coleman and Viliami Moala. The defensive tackles (Mustafa Jalil and whoever replaces Keni Kaufusi) line up in a 3-tech away from the TE, and the rush ends (Chris McCain and Dan Camporeale) line up in a 5-tech away from the TE.

At the linebacker level, you just add a 0 to the technique number to show that they're off the line of scrimmage. So, the MIKE linebacker (Nick Forbes, Hardy Nickerson) will be in a 30-technique (shaded outside the guard, but a few yards off the line of scrimmage) toward the TE, and the WILL linebacker will be in a 20-technique away from the TE. Here's a diagram:

That's the under, which is one of about three fronts that are commonly used in college football and the NFL. Above I mentioned that this is a good front for stopping a pro-style running attack, and we can see why by a comparison with the other two common fronts, the over and the 3-4. Here's the over, which is what you probably think of when you think of the 4-3:

As you can see, the defensive lines in the “over” and the “under” look like mirror images of each other. In the over front, the defensive line is shifted toward the TE, and the DE lines up outside of him. In the under front, the defensive line is shifted away from the TE, and you bring down a linebacker to cover up the TE.

The last common front is the 3-4. The alignment for that is as follows:

So, the DE's play 4-techs, and the NT plays a zero.

The last concept we need to introduce to see the difference between all these fronts is the concept of gap-responsibility. A “gap” is the space between any two offensive blockers. If the defense can cover all of the gaps between offensive blockers, than the RB will have nowhere to go. The gaps between the guards and the center are called the “A” gaps, between the guards and tackles are the “B” gaps, outside the tackles are the “C” gaps, and anything farther outside is the “D” gap:


With all that terminology in place, we can see how these fronts work by looking at who is responsible for each gap in the different fronts. In the over and under fronts, the defensive linemen and linebackers are shaded into individual gaps, and they are responsible for stopping any run through that gap. So, in the under the NT is in a 1-tech, and so is shaded into and responsible for the strongside A-gap (the strongside is the side with the TE). In the over, the NT is in a 1-tech, and so is shaded into and responsible for the weak-side A-gap (the A-gap away from the TE). Each gap is covered by one player, whether it's a lineman or a linebacker, and each player is responsible for only one gap. In the over and under fronts, we say that the linemen are “1-gapping.” One gap defenses let the defenders aggressively fly to their assignment, making them especially disruptive.

The 3-4 is different. Here, the three defensive linemen are responsible for six gaps between them. They line up in even techniques (a 0-tech NT and two 4-tech DE's) and are “two-gapping.” The NT is responsible for both A-gaps, and the DE's are responsible for the B- and C-gaps. The defensive linemen in this scheme are inherently less aggressive because of their two-gap assignments. Their job is to engage the lineman across from them, to read the direction of the run, and to cover the gap that it goes toward. In reality, they aren't supposed to make many plays but rather are supposed to command double teams so that the four LB's can make the plays behind them. I should note that our defense under Pendergast hardly ever played this alignment, if they ever did. We actually based out of an under front and had everybody 1-gapping, which is why you shouldn't worry about our switch to the 4-3. In the old system we had a 9-tech OLB, a 5-tech DE, a 1-tech NT, a 3-tech DE, and a 5-tech OLB. We've left the 9-tech OLB's in the same spot (now called SAM), left our 5-tech DE's and 1-tech NT's where they were, changed the name of our 3-tech from “defensive end” to “defensive tackle”, and converted all of our 5-tech OLB's into 5-tech DE's. There's essentially no difference in the two systems.

Pendergast aside, we can see that the traditional two-gapping 3-4 is drastically different from the over and under fronts in terms of their gap assignments. The under and over are both 1-gap defenses, but they also have important differences. To understand them, we need to understand what offensive coordinators like to attack with the run. Essentially, the offense likes to run to the gaps that aren't covered by defensive linemen. Such uncovered gaps are called “bubbles.” Let's look at the under front again:

In the under, there's a nice bubble over the strongside B-gap between the DE and the NT. When you look at the alignment, you can see why the offense would want to attack that bubble: The OT should be able to seal the DE out of the B-gap while the OG should be able to seal the NT out of it. This leaves the MLB all alone to cover the B-gap, and you can take him out with a lead-blocker such as a FB or a pulling guard. Such a run would be much harder if it were going to either C-gap, because there's a massive DL blocking things up. So, offenses like to attack the bubbles. In the under front there's a bubble over the strongside B-gap and the weakside A-gap. Now we can look at the over by way of comparison:

Here, you can see that the over has a bubble over the strongside C-gap, the strongside A-gap, and the weakside B-gap, meaning that there's one more bubble than there is in the under. The under is tougher against the inside run because it has one fewer bubble for the offense to attack, thus reducing the number of different runs you're likely to see, and certainly limiting the number of runs that are likely to be effective against you.

The second advantage is that the under is strong against perimeter runs. If you look at the under diagram again, you'll see that the offense can not double-team the SLB (the OT can't help the TE, because that would let the DE straight into the backfield), and it will be tough to double-team the DE (the OT will have to get outside of him to slow him up long enough for the OG to get to him). In essence, both the TE and the OT will have to execute “reach-blocks,” meaning that they will have to cross the defender's face and seal him inside so that the RB can get outside. This compares favorably to the over, where the offense only has to execute one reach block against the DE on the edge, and the OT can help the TE get him under control. The same advantage exists on the weakside, making the under strong against outside runs as well as inside ones.

These advantages in the outside run game also make the under a good pass-rushing front. Think about the reason rush ends are so important: They are isolated outside on an OT who doesn't have a lot of help, and you need to be able to take advantage of that. Because of the under's alignment, your DT is in the exact same situation, isolated outside against an OG who doesn't have a lot of help. The under essentially gains you a third outside pass rusher. For this reason, you put your better play-making tackle at DT. Your NT won't have this schematic advantage, so it's OK if he's just a big guy who takes up space. Of course, if your NT can beat double teams and make plays all the better, which is why DeAndre Coleman actually has a chance to be a special player for us. If you notice him much this season, it'll mean that he's performing well above average.

Of course, the front will only look like this against a pro-style offense, and so I think we only saw it once in the spring game. Here's the one snap I found where all of the above comments are applicable:

Here you can see that we have five men on the line of scrimmage. The guy on the left of the line is our SLB and everyone else is where you'd expect them to be, although the MIKE and WILL might be shifted over a little because the FB is offset.

For most of the spring game this isn't what we saw. Nevertheless, we were in the same front. As you start removing offensive players from the box, the under adjusts. When the offense does have a TE in the box, you need to have the SAM on the line of scrimmage to be your contain player. Since the DE is in a 5-tech, the TE will be outside of him and could potentially seal him off inside, allowing a run to go outside. This is why the SAM aligns on the line of scrimmage outside of the TE. It's his job to keep runs from getting to the outside of the defense. When the TE splits out wide or is replaced with a WR, however, no blocker is outside of your DE, and so you don't need your SAM on the LOS. In this case, it is more necessary to have him in position to help in coverage, so he'll move into an “apex” position off the line of scrimmage in between the second WR and the offensive line:

Here's the defense against a 1-back, 2x2 formation. We can see that the DL is still in its under alignment. Toward the top of the screen we have Davis aligned in a 5-tech outside the OT and King aligned in a 1-tech outside the center. To the bottom of the screen we have Keni Kaufusi shaded outside the OG (3-tech), and Ted Agu aligned outside the OT (5-tech). At the top of the screen, Jefferson is in an apex alignment. Against the pass he's responsible for an inside zone, and so he needs to be in position to cover something like a slant by the second receiver, which is why this adjustment is made. At the bottom of the screen we also have two guys lined up at WR, and so Wilkerson has made the same adjustment as Jefferson: He's in an apex position between the second WR and the OL.

Similar adjustments are made against trips formations:

Now there are two extra receivers to the SAM side, and so the SAM moves into his apex position inside the #2 receiver. The MIKE then has to shift to a 50-technique on that same side so that he can cover a slant by the inside-most receiver, and the WILL bounces over to a 00-technique to defend against inside runs. This is still the under, though.

I should say one more thing about our version of the under. When there's a TE, it's easy to decide how to set the defense, because you know that the SAM, DE, and NT will be to the TE side of the formation. When there's no TE (or 2 TE's) the defensive coordinator has a choice to make, because he could just as easily set the front to either side of the offensive formation. In the spring game, it looks like Buh put the DE, and NT toward the passing strength of the offense, meaning that he put them toward the side with more immediate receiving threats (i.e. receivers not in the backfield). So, on a few plays the offense put trips into the boundary*. When that happened, we put the DE and NT into the boundary, because there were more receivers to that side of the formation:

Here, you see that at the top of the screen, toward the trips and into the boundary, King and Davis are in the 1- and 5-tech, while at the bottom of the screen Kaufusi and Agu are in the 3- and 5-tech. The interesting thing about this picture is that while normally the SAM would be playing on the same side as the NT and DE, here Barton is playing to the field and King is playing to the boundary, suggesting that while our DL flips in this situation, our LB's do not. We'll see why this might be so below.

Of course, sometimes the offensive formation has an equal number of immediate receiving threats on both sides of the field (2x2 formations, etc.). Whenever the offensive formation was balanced, we put the SLB, DE, and NT to the field.

This alignment information helps you understand a few more things about the SAM and WILL positions. In Buh's defense the SAM will be an important pass defender, because he'll be lined up right over the TE, will move out into an apex position any time the offense overloads one side of the formation with receivers, and will generally be playing coverage to the field, where there is more space. The WILL on the other hand will generally be to a single-receiver side of the field and will often be aligned into the boundary, where there is less space. What is more, he'll primarily be responsible for covering backs out of the backfield, since we'll have a CB to cover the single WR on his side. This is why our SAM linebackers are, perhaps surprisingly, lighter and more athletic than our WILL linebackers even though the SAM lines up on the line of scrimmage. In terms of the last picture above, where the offense set trips into the boundary, this explains why King, who is bigger and less athletic than Barton, is lined up where we would expect the SAM to be: We want our SAM aligned to the field as much as possible since he's the more athletic pass defender.

To wrap things up, I've already said a little bit about the skills and responsibilities necessary for the SAM, the WILL, the NT, and the DT. Our rush end's job is probably self-explanatory, but he's our primary pass-rusher and will most often be going up against opposing teams' left tackles. The DE is going to be a bigger player and more of a run-stopper because he's to the TE side of the offense and most offenses like to run to their TE's, so he has to be tougher at the point of attack. It is important to note that he still needs to be a playmaker, though. When there is a TE, he's in much the same position as the 3-tech, because he's isolated on an OT while the SAM occupies the TE. When there's no TE, he becomes an outside rusher like the rush end, so he's not just a run-stuffer.

This just leaves the MLB, who has to have the best football instincts out of the whole group, making it no surprise that Nick Forbes and Hardy Nickerson man that position. The MLB has to do everything, from reacting quickly and appropriately when offenses attack the bubble that he's over, to pursuing run plays away from him, to being aware of inside routes in pass-coverage, while also keeping an eye on RB's coming out of the backfield on pass routes. Furthermore, he has to face the greatest variety of blocks. On isolation plays he'll be taking on a FB, on power plays to him he'll be taking on a guard pulling from the opposite side of the formation, and on zone runs away from him he'll be taking on the linemen that are releasing to the second level. The MLB more than any other player can have all sorts of different offensive blockers flying at him from every different direction, and so his mental skill set has to be pretty different from all the other players, who will generally be facing much simpler reads and keys.

That wraps it up for Cal's under front. Hopefully I'll be able to get up a post on our split-safety coverage schemes before too long. I look forward to discussing all this in your replies.

*Remember from a previous post that when the ball isn't placed in the exact middle of the field, the “boundary” side of the formation is the side that has less space, while the “field” side is the side with more space. So, if the ball is on the right hashmark, the boundary will be to the offense's right, because there is less space between the ball and the right sideline than there is between the ball and the left sideline.

This post is AWESOME.

LOL....it is awesome. Now I'll have to set some time aside to actually study all this...

big thanks for dumbing it down though, i'd forgotten some of the terminology...

Great post, interesting stuff.

Quote:

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I should note that our defense under Pendergast hardly ever played this alignment, if they ever did. We actually based out of an under front and had everybody 1-gapping, which is why you shouldn't worry about our switch to the 4-3. In the old system we had a 9-tech OLB, a 5-tech DE, a 1-tech NT, a 3-tech DE, and a 5-tech OLB. We've left the 9-tech OLB's in the same spot (now called SAM), left our 5-tech DE's and 1-tech NT's where they were, changed the name of our 3-tech from “defensive end” to “defensive tackle”, and converted all of our 5-tech OLB's into 5-tech DE's. There's essentially no difference in the two systems.

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Thank You Berk - I will be studying this for the next few days and trying to grasp all the concepts before I will even know what questions I might have.

This is the 1st time I've ever understood what a 5 technique is and other techniques. Makes me feel like I know nothing about defense lol. Thanks for the awesome post

So when is the final for this course? I hope in September so I'll have time to cram after the off season...

Let me add to the chorus - another fantastic post. I played in a gimmicky defense in high school (5-3 "stinger") and things were much much simpler so I have never really understood under/over/etc fronts. We played a number of different coverages but always lined up the same way. We should have a sticky that links to all your football 101 posts.

Great post! It's my understanding that some nickle packages will be worked into the defensive schemes in the fall, any insight into that? Thanks for the breakdown, read it a few times and now it makes sense...well done!

that was dumbing it down?! Sheesh, I so wouldn't get into Cal now...lol...
Thanks to the OP for taking the time and effort....

DLSbear;842129288 said:

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Great post! It's my understanding that some nickle packages will be worked into the defensive schemes in the fall, any insight into that? Thanks for the breakdown, read it a few times and now it makes sense...well done!

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That's something we're gonna have to wait and see on, since I didn't see any nickel in the spring game. The best bet is probably a 4-2-5 over, and my guess is that we'd replace the SAM with the nickel and the WILL with the SAM, if that makes sense. So, the guy who'd come off the field is the WILL, and the SAM would slide over to his spot in the over. The advantage that the normal over has vs. the under is that it always has three LB's at the second level, letting you close down more passing lanes. This is obviously what you want in nickel situations.

To make a little more sense of the over nickel, we can look at the diagram again:


Let's first pretend we're not in nickel personnel. If the TE detaches from that formation, the DE will now be outside the OT and there won't be a bubble for the SAM to cover, allowing him to move into an apex position between the (now detached) TE and the offensive line. He's not necessary in the front, so he can focus on coverage.

When you play nickel you assume that there will be extra WR's, so this is exactly the kind of formation you're envisioning. You pre-empt this by replacing your SAM with a nickel back. Since he isn't tied into the front, you can play him heads-up over the second receiver to his side. From there, you can play all the same zone coverages you'd play in base personnel, but with the NB playing in the SAM's spot. Alternatively, you could play whatever coverage you want with the rest of your defenders but man-up the nickel on his receiver. This is all pretty common nickel stuff, and it doesn't require us to stray very far from our base coverages, so I think something like this is most likely.

they are in my dreams now lol ... great info... nice breakdown now if i can just translate this into Wins on the Ncaa 14 ( lol shut up no smart mouths) and even better and more important the REAL TEAM doing good this year


go bears


hey you got any ncaa tips for me sheesh lol

can we say two words .... GAP INTEGRITY !!!


come on aug 31 geez us ...

Alright Berk! I am even more impressed now as I had one of the players a (LB) double check your break down...I quote, "this dude knows, he even uses the same terms as coach Buh" good job! Ha ha! Not that I doubted you before...

DLSbear;842129334 said:

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Alright Berk! I am even more impressed now as I had one of the players a (LB) double check your break down...I quote, "this dude knows, he even uses the same terms as coach Buh" good job! Ha ha! Not that I doubted you before...

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LOL, that's awesome.

Great post. Think I got it the first time around, but have copied for multiple reads and study. Is the test before Aug. 31?? Thanks loads berk.

Thanks everybody for the kind words. While I have an audience, I don't suppose that anyone more video-savvy than me (and with more efficient software!) would be interested in teaming up on some stuff? If anyone might be interested, feel free to PM me. For now I'm only thinking about videos showing similar plays back-to-back, like a bunch of runs from the spring game, or a bunch of plays run from trips, or that kind of thing. Each of these write-ups would also be well served by video of the plays I take screen-shots of though, so if anyone's interested or has any ideas I'm sure we could do some cool things.

I have a hard time with you tube Berk, can't help you there! Good luck!

Excellent post!

This was a great post - I really learned a lot. Here's my key takeaway.

We will play a modified 4-3 that lines up like a 3-4 and plays like a 4-3. Last year we played a modified 3-4 that lined up like a 3-4 and played like a 4-3.

I have a couple of questions. With all the benefits of the under 4-3, what are the benefits of the over 4-3? There must be some as teams use it a lot. Also what gaps have a bubble in the 3-4? Looks like bubbles in front of both guards but not necessarily for a specific gap. How is that approached strategically?

dajo9;842129385 said:

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This was a great post - I really learned a lot. Here's my key takeaway.

We will play a modified 4-3 that lines up like a 3-4 and plays like a 4-3. Last year we played a modified 3-4 that lined up like a 3-4 and played like a 4-3.

I have a couple of questions. With all the benefits of the under 4-3, what are the benefits of the over 4-3? There must be some as teams use it a lot. Also what gaps have a bubble in the 3-4? Looks like bubbles in front of both guards but not necessarily for a specific gap. How is that approached strategically?

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Good questions. Your points about the 3-4 vs. the 4-3 are definitely what I'm trying to get across. When an offensive coach goes to game-plan they don't ask how many defensive linemen are on the field, or how many linebackers. They ask which side the 3-tech lines up to. They want to know where the bubbles are gonna be. That's what really matters in talking about defenses.

As for your other questions, the over was invented as passing attacks became increasingly sophisticated. By taking an additional player off the line of scrimmage, you can close down more passing lanes. For example, if you use the under against a pro-set then the SAM, because he's on the line of scrimmage, has a harder time against inside routes by the WR, who will be breaking behind him. If you're in the over the SAM is off the line of scrimmage, can see things like slants early on, and can fly out to cover them or make a big hit.

The over also provides an advantage in backside pursuit on plays away from the SAM. When the SAM is on the LOS, he doesn't have a great angle to flow toward plays away from him. The SAM in the over has a much better angle for chasing down runs from the backside, can be a cut-back defender, etc.

The over also gives you different blitz possibilities. In the under, if you want to blitz the SAM he's essentially limited to being an outside rusher and probably won't go any farther inside than the C-gap. In the over both the SAM and the WILL can blitz either outside or inside gaps, giving the defense more versatility in that aspect of the pass rush. Really, what all these advantages get you is that the over is a more balanced front. You give up some of the advantages of the under, but the advantages that you do have are present on both sides of the formation. For all these reasons, the over has become especially popular with the rise of spread offenses.


Those were philosophical approaches to the over/under distinction, but there's also a more practical one. Imagine that the offense is in 21 personnel with the TE to the field. Right before the snap, the offense does a kind of motion called "Y-trade," where the TE motions from the field side of the formation to the boundary side. Now your rush end is outflanked to the boundary by the TE, and your SAM isn't really doing anything. To stay in the under as drawn up on the chalk board you'd have to flip your entire front, which is risky right before the ball's about to be snapped. It's much easier to shift your rush end over the TE and to back your SAM off the line of scrimmage. These two slight adjustments put in in the over which, as we've seen, is a sound front with its own advantages. This is an automatic check for Nebraska, for example. I'm not sure how Cal would respond to Y-trade, but that kind of environment is a case where the over can be a useful quick-fix.

As for the 3-4, it has sometimes had the unfortunate nick-name "double-bubble" because, you're right, the main bubbles are over the two offensive guards. The bubble isn't so much about the gap itself, as it's about the presence of a natural place for the OL to create a hole. So in the under, the B-gap is the bubble because the guard can easily seal the NT away from the hole and the tackle can easily seal the DE away from the hole. You're right that in the 3-4 the bubble isn't over any one gap per se, but we can also see that the space over the guard is a pretty natural place to create a hole anyway, and a place that OC's are likely to attack. If the defensive linemen aren't monsters, the 3-4 can be much worse against the inside run because the bubble is kind of over BOTH the A- and B-gaps, meaning that the OC can call just about whatever inside run he wants. Nonetheless, it is true that runs are drawn up differently against 4-3 vs. 3-4 ones for exactly the reasons you're intuiting.

I'm just an average bear that wants to keep up with cal football. I might as well have read @#*$^*@&#^$*&^#@&(*#@&%(()($@*%@#(*^$*&#@^$*&@# instead. LOL Anyway, GO BEARS.

icecream12345;842129407 said:

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I'm just an average bear that wants to keep up with cal football. I might as well have read @#*$^*@&#^$*&^#@&(*#@&%(()($@*%@#(*^$*&#@^$*&@# instead. LOL Anyway, GO BEARS.

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if i did not play ea college football i would be as lost as you lol jp

In my opinion, one of the great things about this write-up is how easy it is to understand. Yes it is intimidating with the length, jargon, and technical detail. But if you read it one sentence at a time and look at the charts it actually all comes together very nicely. Great job OP.

<- Never played organized football or game system football

Great post Berk18, but aside from the circles, squares, numbers, letters, photos and technical writing, what does this say about the quality of Cal's D? For example many "experts" in the media seem to be underrating Cal's D based on the fact that it is a new system. Similarly, Cal is listed as having only 5 or 6 "returning starters" on D, but you can count more if you include guys who have changed positions if those positon changes are minor (i.e. from OLB to DE).

Based on what you know about the system Cal is now using under Buh, do you think Cal's D is going to better than average, underrated or what?