Pass Protection Scheme Basics

Cal's pass rush has been a major problem for three of the last four years, and is one of the most-discussed topics among the fan base. It would technically be possible to break down our pass rush and to talk about all of the things that we could be doing instead of what we actually do, but trying to predict the hypothetical results of such changes would be too speculative and abstract for my tastes. Instead, I'm going to defer to the actual DC's in the conference by writing a series of posts breaking down some of the best pass rushes in the PAC-12. As of right now, I'm planning a series of individual posts on Colorado, Utah, and Washington. In 2016, those teams were the three best in terms of sacks per game against PAC-12 competition. Depending on how things go with these posts, there's a second tier of ASU, Stanford, and UCLA that could be worth going into.

Before we get into the pass rush posts themselves, however, I'm going to say a few things about the basics of pass protection; the pass rush makes less sense if you don't know what it's designed to defeat, so this post will serve as a quick introduction and as a resource for my later posts on various rush schemes.

Basic Pass Protection Assignments

On most normal drop-back passes, there are two common assignments that an offensive lineman might have. He could be in slide protection, or he could be in man protection. Remember that every offensive lineman has a gap to his left and a gap to his right. In slide pass protection, that lineman will only be responsible for one of those two gaps. He will slide into that gap, and will pick up any pass rusher that shows in it. He is not responsible for pass rushers that rush to the other side of him. We can illustrate this by focusing on the LG's responsibilities versus two different stunts in the following diagrams. Let's assume that he's sliding to his left:

  Against each of these stunts, the LG is only responsible for the gap to his left. In the first diagram, that means that he's responsible for the DT. The blitzing SLB will be someone else's responsibility. In the second diagram, he slides left and is therefore responsible for the SLB. The DT in this diagram will be picked up by someone else.

Slide protection simplifies things for that LG, and will make it both mentally and physically easier for him to execute his assignment; because he's only responsible for one gap, he can play aggressively toward that gap. He doesn't have to read and react to the movement of any specific defender, and he doesn't have to worry about getting faked out. He just has to step to his left and block whoever shows up.

This contrasts with man pass protection. In man pass protection, that LG will be responsible for one specific player (probably the DT), and will block him no matter which side he rushes to. Here are the same two stunts that we saw above, but with the LG in man pass protection:

  Here, the LG is manned up on the DT, and is responsible for him no matter which side he goes to. The SLB will be someone else's responsibility in both of these diagrams. This kind of protection simplifies assignments in a certain way, since the LG knows who he is blocking no matter what. It makes his assignment more difficult in other ways, however, because he has to be ready to react to a pass rush move to either side.

Although this is called man pass protection, it isn't man in the same sense as man coverage in the passing game. The LG won't chase the DT no matter where he goes. You don't want several 300 pound linemen running around and trying to stay out of each other's way while chasing twists and all of that. Instead, if the LG's man doesn't rush into either of his two gaps, then he's going to pass him off, keep his head on the swivel, and wait for someone else to attack him:

  Here the LG is manned-up on the DT, but the DT goes outside and doesn't attack either of the LG's gaps. He therefore passes off the DT to the outside, and waits for the DE to attack him inside. Now the LG is manned-up on the DE, and the LT is manned-up on the DT. This process of passing off man assignments is difficult in its own right, of course, and puts a premium on your OL's ability to communicate and work together in making sure that every pass rusher gets picked up.

Pass Protection Schemes

Those are the two assignments that any one lineman will probably have. Now we can look at how these assignments can be distributed among all of your blockers. First, let's look at a scheme that is man protection across the board. This kind of scheme is typically called B.O.B. pass protection, which stands for “Big on Big,” or “Back on Backer.”

Let's assume that we're facing a 4-3 defense. If we're in B.O.B. protection, then my five offensive linemen will be in man pass protection and will, as a unit, be responsible for the four defensive linemen plus one designated LB (usually the LB who is the biggest blitz threat). If a LB other than the designated one blitzes, then that will be the RB's man. In the diagram below, we'll assume that the MLB is the LB designated for the OL:

In this diagram, we see a 6-man pressure with the MLB and WLB blitzing. The OL is responsible for the four defensive linemen plus the MLB, since he is the LB designated for them. The C will, therefore, man up on the MLB when he blitzes, and the other four OL will man up on the DL. The WLB isn't designated for the OL, and so when he blitzes, he will be the RB's man. As you can see from these assignments, B.O.B. protection guarantees that your best pass blockers (the OL) are taking care of their best pass rushers (the DL + biggest blitz threat at LB). This is a benefit that other kinds of protection won't have, as we'll see below.

B.O.B. will let us account for one specific combination of six pass rushers. If a rusher who isn't a part of those six blitzes, then it will be up to the QB to account for him by throwing hot:

  This is also a six-man pressure, but now the SLB and WLB are blitzing instead of the MLB and WLB. The OL is still responsible for the four DL and the MLB. The LT and LG are manned-up on the DE and DT, and so they still block them when they rush inside. The C and RG are responsible for the NT and MLB. When the MLB doesn't come, the C helps the RG with a double-team on the NT. The RT is manned-up on the rush end, and the RB is manned-up on the WLB.

The big question now is, “How do we account for that blitzing SLB?” If he comes, then it is up to the QB and WR to sight-adjust and throw hot into the space that he is vacating. In the diagram above, I've drawn the X receiver sight-adjusting to a slant against the SLB's blitz. This is a good answer if you're fine with throwing the slant here (or some other hot route). A downside of this protection, however, is that the defense can dictate this throw if they can figure out which LB (or DB) is unaccounted for in your blocking scheme. If you need more than the ~5 yards that the hot route can provide, then the defense can just blitz that SLB, force you to throw hot, and be happy that you completed a five yard slant when you needed 8 yards. If an OC wants to keep his job, he needs an answer other than just throwing hot all the time against the blitz.

One answer to this problem could be full slide protection. In this scheme, the entire offensive line will slide in one direction. Let's see how the same stunt that we saw above would get picked up in full slide protection:

  When we slide the OL to the left, the QB no longer has to throw hot if the SLB blitzes. We can now account for the SLB, because the LT will be sliding into that outside gap to pick him up. This means that the QB can now sit back and read whatever play we're running like he normally would. To the inside, the LG and C are also sliding left, and so will pick up the DE and DT when they rush inside. The RG will slide left and pick up the NT.

It's important to note that in full slide protection we can still block the MLB if he comes instead of the SLB:

  If we get an MLB blitz like this, then we'll still be able to pick him up with the sliding C. This flexibility to pick up either the SLB or the MLB, then, makes this protection more versatile than B.O.B.

To the backside, full slide protection will also change assignments against the WLB and rush end. In B.O.B. protection, the RT was manned up on the rush end and the RB was responsible for the blitzing WLB. In full slide protection, the RT will slide left and pick up the blitzing WLB. The RB is not a part of the slide, and will be responsible for sealing off the backside edge. In this case, that will make him responsible for the rush end. This can create some strange matchups. Let's look at this diagram again:

  In this case, we are wasting two offensive linemen (the LT and RT) by having them block LB's. Since we've been assuming in this post that the MLB is the defense's biggest blitz threat, then they aren't even blocking particularly dangerous LB's. Meanwhile, you've got your RB (probably your worst pass blocker) matched up on their Rush End (probably their best pass rusher). This isn't an efficient use of resources, and can cause some obvious problems.

One way to fix this is with half slide protection. This protection will slide only a portion of the OL in one direction (it can be more or less than a true 50% of the OL in the slide), and then will play with man protection on the back side. Here's that same stunt against half slide protection:

  In this diagram, the LT, LG, C, and RG are all sliding left. This will let them pick up the SLB's blitz just like they would've in full slide protection. The difference is that we are now stopping the slide before the RT instead of sliding the entire line. Now the RT is manned-up on the rush end, and the RB is manned up on the WLB. This can be a bit of a panacea if we call the slide in the right direction. If we guess wrong, though, then the man side of this protection is vulnerable to the same problems that we saw for B.O.B. above:

  We're still half-sliding left in this diagram. This is still a six-man pressure, but now the WLB and SS are blitzing, as opposed to the various combinations that we've seen above. We have four blockers (LT, LG, C, RG) sliding left to block three defensive linemen (the DE, DT, and NT), while the defense is bringing three pass rushers (the WLB, Rush End, and SS) to overload our two blockers in man protection (the RB and RT). Now we're wasting an offensive lineman (the C in this case) by having him block nobody, and we're stuck having to throw hot to account for that SS blitzing off the edge.

Conclusion

What this discussion of various protection schemes shows is that the match-up of the defense's pass rush vs. the offense's pass protection is its own game within the game. As an OC, you would ideally not be too predictable in who you choose to block or in how you choose to block them. As a DC, you want to figure out how your opponent protects the passer, and you want to call a pass rush that stresses the vulnerable points within that protection scheme. All of these strategic considerations are, of course, liable to change with all of the usual factors including down, distance, score, personnel, formation, spot on the field, time remaining, etc. This strategic back-and-forth is probably the most under-appreciated aspect of both defensive and offensive playcalling, and often gets reduced to “blitz more guys” and “keep more guys in to block.” In reality, this aspect of the game is one of the most complicated. If you look back through this post, you'll see that every blitz is a six-man pressure. This was meant to show that the same number of blitzers can have completely different impacts on the offense's blocking schemes depending on the quality of the playcalling and the blitz schemes that are used. In the remaining posts in this series, we'll see how all of this unfolded in actual games in 2016, and we'll see how some of the best coaches in the league negotiated this very challenging subject.

For questions/further discussion, head to the BI thread here:  http://bearinsider.com/forums/showthread.php?104868-PAC-12-Pass-Rushes&p=842778989#post842778989