Colorado and the Promise and Perils of Cover 0

[dt_divider style=”thick” /]The Colorado Buffaloes 2017 season was one of regression, with major steps back in just about every notable defensive category. They set at least 3 year worst marks in: points per game, total yards/per game, rush yards per game, yards per carry, pass yards per game, yards per play, and total sacks. Not great.

That being said, they were returning just 3 starters on defense from the 2016 squad that sent them to their first bowl game since 2007 and had four defenders drafted. Defensive coordinator Jim Levitt left after the 2016 season for the same position at Oregon and new coordinator DJ Eliot was in his first season with the group. There’s certainly reason for optimism, or at least expecting some improvement on last year’s numbers, going into 2018.

One thing Eliot brought to the Colorado defense, to its benefit and detriment, was a Cover 0 defensive package. Cover 0 is a man coverage scheme without any deep coverage players. In general, it involves a heavy blitz component with the defenders who aren’t in man coverage. Occasionally, underneath defenders will spy the quarterback or hang as “rat defenders” in the underneath area. Regardless, at its core, Cover 0 is man coverage without any deep safeties.

With the lack of a deep coverage player to stop big plays, Cover 0 obviously has its drawbacks. However, if the blitzes in front of the coverage are creative, and the defensive backs can hang on an island long enough, it can be deadly for offenses. Colorado dealt with both ends of the spectrum in 2017, and as their defense matures and grows under Eliot, we should continue to see him trust his players with the responsibilities of Cover 0 in 2018.


Cover 0 has some serious upside as a coverage if your defensive personnel can handle the more dangerous man coverage on the back. There were multiple examples on film of Colorado succeeding when calling Cover 0. Success was seen in a couple different ways, whether that was man coverage defenders staying in phase long enough or the overload blitz forcing a quick throw from the QB. But, overloading the box with defenders when planning on Cover 0 can also have some positive effects on run defense, which we’ll also examine here.

This first example comes from Colorado’s game against the UCLA Bruins. Colorado will call Cover 0 with a 6 man blitz scheme up front early in the fourth quarter while trailing 21-20. They’ll will load the box and show Cover 0 pre snap. UCLA comes out in 11 offensive personnel with trips to the right.

UCLA will run a flood/sail concept here to the right, with a curl/flat concept on the left side from the X receiver and RB. Colorado, as expected, runs Cover 0. They’re in man coverage across the board with 6 pass rushers.  

Obviously, Colorado is relying on their defensive backs to stay in man coverage here. But the ideal situation for them would be if the pressure gets home and forces an errant throw. However, even though there are only 5 blockers against 6 rushers, UCLA blocks this up pretty well at first. Box safety Ryan Moeller (#25) gets chipped by the tight end as he’s releasing so he’s hesitant to pressure.

If the Colorado defensive backs don’t hold up at the snap, quarterback Josh Rosen (#3) has time to throw. However, the DBs do a great job of staying in phase (especially the CB at the top of the screen) to force Rosen off his spot. Moeller is able to rush freely once Rosen leaves the pocket and force an errant throw.

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If you watch the DBs for Colorado all across the screen, they do a great job of hanging with their man without any deep safety help. If your DBs can hang in man alone like this, Cover 0 becomes a very viable coverage, regardless of whether the blitz gets home immediately.

This next play, from the Buffaloes’ game against the Cal Bears, is a good example of Cover 0 succeeding in the opposite direction, with the blitz forcing pressure rather than requiring tight coverage downfield. Here, Colorado once again brings a 6 man pressure scheme with Cover 0 in the backfield. Cal has trips to the left, and they’ll run a Hank concept to that side of the field.

Here’s the offensive and defensive playart:

The slot receiver to the top of the screen running the flat route actually comes open on this play, as safety Evan Worthington (#6) is playing with inside leverage since it’s Cover 0.

The quick pressure from the blitzers, though, force QB Ross Bowers (#3) into a quick throw without proper footwork. Bowers is looking to hit the slot receiver on the flat route, but you can see below his foot position when he makes the throw, as well as where the defenders are in relation to the QB.

The pass is very inaccurate, and Colorado successfully forces a 4th down in the third quarter.

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So that’s two ways that Cover 0 can result in a big positive for the defense: either through tight man coverage or through getting a blitz through the blockers for quick pressure. One other big advantage of Cover 0 is that it allows for a numbers advantage in the run game for the defense. Prepping your defenders for a blitz allows the defense to overload the interior, especially when trailing late in the game.

This play below is a great example of that, from Colorado’s game against Arizona. You can see how Colorado has overloaded the box to play the run while trailing late in the fourth quarter. They’re trusting that if Arizona is going to throw, their DBs can hold their own long enough for a blitz to get home.

Colorado needs to stop the run this late in the game, so they sell out and trust their DBs with Cover 0 if it’s a pass. The run D steps up.

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Obviously, though, playing man coverage without any deep safeties can lead to… issues. If the blitz gets picked up, defenders are hung out to dry without help over the top.

Earlier in the Arizona game, there’s an example of the perils that Cover 0 can have on your defense if things don’t work out early in the rep. Arizona comes out in a 2×2 set with a tight end to the left. The tight end will stay in to block, while the Z receiver to the left will run a fade. The two receivers to the right will run a double post concept.

Here’s Colorado’s defensive alignment:

Rather than blitzing like they’ll often do, Colorado only rushes four on this play. They’ll drop linebackers into underneath coverages as “rat” defenders to cut off any quick hitting routes. But, there’s no deep defenders to stay over the top.

The double post concept on the right is a tough one for the defensive backs to defend if pressure can’t get home early in the rep. With the pressure getting blocked up well by the Arizona OL, QB Khalil Tate (#14) has time to sit back and hit the slot post route over the middle.

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With no deep help from a safety, slot corner Nick Fisher (#7) gets beat inside since the receiver has a two way go. Fisher can’t play with leverage either way because he doesn’t have help over the top. He’s beat with an outside – inside move, and the slot receiver gets open over the middle deep in the field. Tate hits him for a big play.

This last play is another example of some of the downsides of Cover 0 for Colorado, this time from their game against the USC Trojans. Colorado will drop into a similar coverage as above, a Cover 0 defense with rat defenders underneath. There’s a few examples on film of Colorado struggling when running this look, since it still doesn’t have deep coverage defenders but lacks an overwhelming blitz look.

Here, USC will run an RPO design, with a power run to the left and a slant route from the right side slot receiver. QB Sam Darnold (#14) sees man coverage pre-snap, and trusts that his receiver can beat his defender inside quickly off the line for a bit of separation.

Darnold simply needs to read the edge player, safety Evan Worthington (#6), to decide whether to hand the ball or throw it to Deontay Burnett (#80) on the slant. If Worthington gets upfield against the run or to attack Darnold, the QB will hit Burnett. If Worthington sinks underneath, then Darnold will hand the ball to RB Stephen Carr (#7).

Worthington gets up field to fill the void left by the right tackle pulling on the run. That means Darnold needs to throw to Burnett. Worthington is attacking Darnold, so the QB pumps to pause Worthington and buy Burnett another second to get open inside. Burnett does his job, and so does Darnold.

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This play ends up in a touchdown for the Trojans in large part because of the Buffaloes playing Cover 0. There’s no defender in the deep part of the field to make the touchdown saving tackle. With all the linebackers crowding the box, which is a dubious call on first and goal from the 18 by the way, the defensive backs are totally alone, even on quick hitting routes like slants from the slot.


Cover 0 is the ultimate risk in football, especially when it’s combined with a blitz rather than rat defenders. With Colorado’s defensive backs they were able to play Cover 0 for long enough to let a blitz get home. However, as you can see from the final two plays, Cover 0 with rat defenders hanging underneath is a tough ask of any DBs.

Looking ahead to the 2017 season for the Buffaloes, expect another solid dose of Cover 0 on D. Blitzing for fast pressure and trusting your DBs was a recipe for success for the Buffs. However, they struggled when tasking linebackers with underneath coverage, as it still prevented deep help for the DBs but didn’t lead to quick pressure on the QB. With some adjustments, the Buffaloes defense can definitely step up their Cover 0 ability.

Follow Ryan on Twitter @DBRyan_Dukarm. Check out the rest of his work here, including his look at what Chip Kelly’s run game will look like at UCLA and his study of what effect making a pre-draft visit has on being drafted.

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