Wisconsin pass
gotchya [Patrick Barron]

Neck Sharpies: Trapping the Slant Comment Count

Seth October 30th, 2018 at 10:38 AM

Waaaaay back in the nonconference portion of the season Michigan was getting repeatedly gashed by slants. The problem hit a crescendo against SMU, and their excellent little slot bug James Proche.

SMU threw six slants for 44 yards on 4 completions; only on the last did a safety make a play on the ball, and there’s a big reason for that we’ll get into further down. As the season’s progressed, however, Michigan’s gotten much better not just at defending slants but convincing opposing offenses not to even bother with them by running trap coverages. Why were we bad at them before? Is that a hole in our base defense? What’s a trap coverage? Let’s discuss.

Defending Slants and Fades with Man Coverage

The reason Michigan was bad at slants was they were bad/unlucky last year at fades, and made a conscious decision to be align in a way that made fades harder and slants easier.


Michigan likes to run a lot of Cover 1: man to man defense with single high safety. They also like to blitz their linebackers and play them aggressively against the run. The coverage has help inside on deep plays but no help outside, and small help underneath. Offenses learned long ago that you can put a Cover 1 slot defender in a bind by threatening him short/inside (a slant) and deep/outside (a fade). Both routes start by running directly at this guy, trying to get him to flip his hips to defend whichever of the two you’re not running.

[After the JUMP: a wild Mon Calamari appears]

Slot defenders expecting one or the other can “cheat” by alignment. It’s not equal: defending a fade means flipping around and running with a guy who doesn’t have to change direction, while on a slant it’s the defender who gets to break directly toward the ball while the receiver has to run twisted. 


Of course you can align inside if a fade’s not a concern, such as in a goal line situation, e.g. the one successfully defended slant vs Cov1 in the SMU game. Look where Metellus lines up here:

#14 just below the bottom hash

That has been rare. On the slot-fade defense slider, Michigan went into this season with the bar set all the way to fade. The hope was their safeties were experienced and athletic enough to deter fades by alignment and still be able to drive on slants, at least enough to make slants a bad play. Against a serious man like Proche that was incorrect, to the tune of 8.8 yards per attempt when they tried it. SMU also threw four fades; one drew a ludicrous flag from the rent-a-refs, and one was a ludicrous catch that passed through a defender’s arms and was caught on Proche’s inside arm and hip (not exactly how they draw that up). All of them were far likelier to be intercepted than caught by a receiver, and SMU soon abandoned them rather than continue to try their luck. But that was Proche. How was the rest of the season going:

NEBRAKSA: Frost certainly wanted to try the slant but after SMU he didn’t trust Brown to keep his linebackers from dropping into them, so he added a Run-Pass Option. It’s here if you want to watch it but not really relevant because Nebraska was in an illegal formation (not called, because the John O’Neill crew is worse at their jobs than the MSU beat is at theirs) and the defense (as a player’s parent clarified to me later) decided the slot defender heading downfield wasn’t eligible.

NORTHWESTERN: This game was even more slanty than SMU. I clipped 14(!!!) plays on the drive back from Chicago that I thought a slant was the primary read. It was quite simply Northwestern’s gameplan to have Thorson throw slants, mostly at his slot receiver, and Michigan’s gameplan was to let them try. Note where Kinnel is lined up on this one relative to the slot receiver. Thorson threw the backside slant but Kinnel was beat more than Long:

Northwestern ran this again, and again, and again, and again, and again (vs Cov2), and again and again:

…before Don Brown finally dropped his linebackers into specifically “F yo slant” zones.

Why Not Drop the Linebackers?

My theory of defense is there’s three ways to win a down:

  1. EXECUTE: Run a vanilla play that’s sound against most things and everybody executes.
  2. ROCK, PAPER, SCISSORS: Run a special—read: normally unsound—play that’s designed to beat the offense’s playcall, and
  3. DOMINATE: Have a guy make a great play despite starting in a disadvantageous position.

For Michigan’s base Cover 1 defense, dropping the linebackers into the alleys in this way is #2, i.e. Don Brown is throwing paper on Northwestern’s Rock. It’s unfortunate (or perhaps a last second minor course correction) that Thorson was so inaccurate on this ball because otherwise it’s picked. Ditto when Wisconsin came out with slants, Devin Bush batted it, and a Badger receiver caught it (though short of the 1st down):

This is certainly a response, especially on 3rd and long, but it’s untenable given how Michigan wants to play. A Don Brown defense wants to sell out against the run as much as possible. They don’t want linebackers dropping out of the middle all the time like weak-ass Buckeye OLBs. We want them jamming up running lanes, flying to ball, and threatening all kinds of blitzes. Sure, once in awhile they’re going to drop back, but the defense’s whole identity is Devin Bush looking hungrily at your rib cage.

To get that, Michigan had been asking their secondary to pull off #3, and running their base Cover 1 so much that opponents could expect it and gameplan for it—sitting on the fastball if you will. What Michigan really needs to shut down the slants is a two-seamer, a different OPTION 1: a hale defensive base strategy that still fits their philosophy.

What could that be?

…psst Ackbar, your cu—

Trap Coverage

Don Brown wonks have been looking for this since we first got our hands on his Boston College playbooks.


Another victim of that version of Powerpoint that treated lines as shaded objects

Brown's trap coverage moves the cornerbacks into the slots, covering any leaky outside receivers with the safeties reading outside-in. The squigglies mean the defender is shuffling to that spot, not running. The numbers refer to the receivers, counting from outside->in. Any eligible receiver who pops out a side gets added to the number, so if you've got #2 and the RB goes out in the flat, you've got the RB. In this coverage the safeties only have the #2 receivers if #1 is taken care of—until such time they're the OLBs' problems.

This was an oft-used defense for Boston College—the playbook even notes that "Eagle" is their base call when they get tempo'ed unless they've set a different call that week. But for Michigan it's been a rare pitch. I found one play I was pretty sure was trap coverage and one that used a trap trick for Michigan's base Cover 1 between Northwestern or SMU's slant-a-thons. But Michigan did break out the ol' trap against Wisconsin, and immediately got a pick from it.

That was a curl-out route, not a slant, but attacks the same spot as a slant, and the description in the video above is a pretty good one. I would add that the reason it's called a Trap is because you're baiting the quarterback to throw into this area by showing him a look that would suggest the cornerback is about to vacate the area, and then he doesn't.


Look at all the grass behind David Long where they've drawn a yellow teleprompter line. Look where the safety is playing: on top of the tight end. A quarterback who's played against Cover 2 and Quarters teams will reasonably conclude he's looking at a nice soft Cover 2 shell, and know that he's got a nice, safe throw into all that room underneath it. It's only after he releases the ball that he realizes the cornerback wasn't vacating the premises:


What do the cornerbacks have to do to earn such a coverage reprieve? Why, defend the run of course. Here's Zordich when he teased trap coverage in a 2016 preseason presser:

MGoQuestion: If we could talk trap for a little bit, how do you coach that for your guys? Is it brand new to them?

“I wouldn’t say it’s new to them. For them, it goes back to high school days when they were playing cover 2, when they were hard corners. Their read has got to be the end man on the line of scrimmage, so it’s really nothing new as far as they have to deal with. It’s just that it’s going to be more often than what they’re used to from I’d say a year ago.”

They're in the slot, and slot work is about being an edge run defender, especially in this defense that stops the run first. This can be a nice surprise against a team that likes to run out the sides and suddenly finds an edge setter already hanging out there like Lavert Hill in this example from the Penn State game last year:

#24 the cornerback at the bottom of the screen:

There are some other pieces to it so they can run it against any look without being unsound. The cornerback and safety are playing the coverage together and a cornerback may at times have to take the #1 WR (for example when two receivers are stacked). If the corner calls an "INVERT!" the safety takes that curl/flat zone and the corner backs into the deep job, reading 1 to 2.


I couldn't find a direct example of this but we saw something similar to an Invert on a couple of 2nd half slants vs Northwestern:


This is a Trap tweak to Michigan's normal Cover 1 but works the same as a trap, or should—Kinnel oversold his deep middle third and came up too late but the way this was drawn up should have been an interception.

Watch Metellus (2nd guy from the bottom) bail to a deep zone while Kinnel hammers down. It's a big hit that should by rights have jarred this ball loose, but the design was for Kinnel to dive in there in time for a pick:

They ran something that might have been a true trap invert in the 4th quarter. Watch how Hawkins (the high safety on the bottom of the screen) screams down:

Thorson by now has gotten wise to Michigan's attempts to mess with his slants so he rolls out and tries to find something on the other side, so we can watch the trap coverage develop over a longer play, with the CB (Watson) and S (Metellus) swapping guys as they twist, converting into a more normal Cover 2. Hudson didn't drop far enough and gave up the completion and that's an issue with this coverage: the OLBs become virtual safeties with deep dropback hash-to-the-numbers zones and a lot of ground to cover, and even the hybrid safety of the defense is not wholly comfortable with that.

Another tweak is to play the receiver outside off press man before showing the trap coverage. Michigan won't do that if the cornerback is the only defender between the last guy tight to the line and the sideline. Watch Long on the second Badgers trap:

#22 cornerback at the top of the screen

With no run threat out there the cornerback is free to start out more like those sticky match zones like MSU (Quarters) or Alabama (Pattern-Matching), with the corners up on the #1 receivers and everybody spending the first few seconds with the man they're lined up over.


At the snap it looks like Tampa 2, with the OLBs widening to "buzz" (cover over) a quick attack to either #2 target. Long is mostly cut off by the director's Wisconsin zoom but you can see Long's feet at the top to get the point: they're OUTSIDE of the receiver.


This tells the quarterback that Long believes he has help inside. "Where's that help inside?" thinks the man turned on by the undulations of a rill. "Ah, yes, the linebacker currently buzzing the tight end. As soon as my tight end curls beneath that I've got an easy pass."


"I've got you" thinks Randy Rivers, and he releases the ball to the spot his tight end should soon be inhabiting peacefully. The trap is set. And while the quarterback's eyes are fixated on his target, it is sprung.




On these plays the trap coverage isn't just a deterrent—it puts a cornerback in a spot the quarterback's coverage read doesn't expect him to be. Seconds against Michigan's pass rush are precious, and wasting them on a slant that isn't going to develop can cost a down or worse. Giving up a pick because the cornerback gave a false read is much worse.

It's not a panacea. The run defense benefits from two edge guys hanging out near the line of scrimmage and everybody facing the play, but drifting back linebackers still creates space that even the worst team can exploit:

Michigan doesn't have to run these all time time with all their associated blitzes like Don Brown did with BC. Those Eagles were a base Cover 2 team that used trap almost as often. They also ran it out of a 3-3-5 and used all sorts of OLB blitzers to entice a false hot read from the QB thinking the blitz means the slot was abandoned.

Michigan would stay in their Cover 1 blitzing linebackers all day if they could—and maybe the next wave of athletic safeties might give them the ability to dominate slants from a difficult alignment. But having the trap, especially given how much more Cover 2 they're running this year to compared to last, is a nice deterrent to have on film, with little downside and a huge payoff when it catches a QB with a lazy read.



October 30th, 2018 at 11:32 AM ^

Loves me some neck sharpies!!!

Been watching UM football for 45+years and have never understood what I'm watching so well as since I started reading your posts.

Being a lazy-ass MFer, I'm going as my classmate coach HardBalls for Halloween (I hope I have some clean khakis in my closet.)

You can bet I'll be accesorized correctly with a pen hanging from my whistle.


October 30th, 2018 at 11:39 AM ^

I'll reiterate just for the record that Brian observed -- and Don Brown later directly confirmed in his post-NW presser, h/t MGoBlog -- that the vulnerability to slants was a deliberate decision to dissuade those fades.  They'd rather you get 6-8 yards than 20-30.  Slants were going to be addressed at some point, but it took adding new wrinkles to the coverage.

(skip to 1:08, the start time didn't work)


October 30th, 2018 at 11:55 AM ^

Relieved this isn’t a rundown of blocking technique on trap runs. /s 

Informative stuff. Guess I’ll have to reread when I have more time to digest some of the subtleties of it. 

Ron Utah

October 30th, 2018 at 1:21 PM ^

I think what’s important for fans to remember—and what this post points out—is that there is no such thing as a perfect defense. Defense is like a blanket that’s just a bit too short: cover your feet and your shoulder get cold, pull it up to your shoulder and your toes are bare. 

I love the traps and different looks Brown has deployed this year. I’d also like to see more robber coverage where a safety comes underneath. The downside there is it puts a LB in coverage. 

This is another great post. Thanks, Seth. 

Space Coyote

October 30th, 2018 at 1:51 PM ^

Traditionally, there are two scenarios when Brown wants to run "Invert", where the safety has flat responsibility and the CB takes the deep 1/2

1) When the offense is in a nub formation (i.e. there is only a single, in-line TE to that side of the formation, with no receivers outside of him). This limits the offense to one vertical threat to that side of the formation, and Brown will often "invert" the coverage pre-snap (i.e. have the safety aligned 5x5 yards off the end man on the LOS and the CB aligned deep). This gets a better run defender near the ball and allows a CB to do what he's best at: cover.

2) When there is only a single vertical threat to the side of the formation that can't be covered by a LB. So in a lot of 2x1 formations, for instance, you may see the coverage become inverted because, again, it allows a safety to come down in run support (better for angles) and allows a CB to do what he's generally good at: cover. 

The reason for this is inverting the coverage against two vertical threats really puts the safety in a bind he can't win. The idea with trap coverage is that it converts to man if both #1 and #2 go vertical. That can happen because the CB has outside leverage reading the release of #2. It is much more difficult for the safety to play both the flat and vertical with that read. I thought Michigan ran it at least twice in one game (think it was in non-conf but struggling to find it) in which Hawkins was late buzzing down; may want to check there.

Michigan also ran a lot of trap against JT in last year's OSU game that caused a ton of early game issues for OSU. LINK


October 30th, 2018 at 4:42 PM ^

It's how many deep safeties you have. If you watched the long mcsorley run last weekend, Iowa was in cover 0. As in no saftey was deep, they were in man close to the line. Cover 1 is what Michigan has run the majority of the time the last 2 years, with one safety deep and the other in the box (typically in man on a slot). Finally, you have cover 2 safties with both out of the box, usually 10-12 yards deep. Typically, this means they both will have deep half responsiblites.


October 30th, 2018 at 5:33 PM ^

Cover 1 is basically man to man with a high safety (the 1) who can cover for any mishaps in the run and give help against posts.


Cover 2 is your standard split-the-field zone defense. Everybody is facing the quarterback, everybody has an area they have to cover, and you carry anyone who enters your zone until he enters the next zone and the guy playing that zone can pick him up. 



October 30th, 2018 at 11:13 PM ^

In watching Kinnel's hea pre snap his eyes are never set. He's slow to read the slant route thus making it an even easier catch. His eyes should be positioned so he can see when the ball is snapped and the WR's first few steps. Instead he move's his head and see's one or the other. 


October 31st, 2018 at 6:21 AM ^

This is great. It may be well known to some but it really helps! To paraphrase Yogi Berra, "you can see a lot by watching" but you have to know what you are seeing.