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How the 49ers defense can limit the Chiefs spread concepts in the red zone

Film room looks at how the 49ers can counter the Chiefs offense, and some of the ways the Chiefs can frustrate the 49ers defense.

San Francisco 49ers v Kansas City Chiefs Photo by David Eulitt/Getty Images

With the big game set for this Sunday in Miami, we’re going to not-so-briefly cover what the 49ers can expect to see from the Chiefs offense and how they might counter the multiplicity of head coach Andy Reid’s offense and the plethora of weapons they have.

The Chiefs finished the regular season 12-4 and earned the second seed in the AFC behind Baltimore. With Baltimore’s loss in the divisional round to the Titans, the AFC Championship game would then go through Kansas City. The Chiefs roared back to beat the Texans after being down 24-0 early in the second quarter by a score of 51-31. In the AFC title game, they found themselves down again at one point 17-7 before eventually taking the lead going into halftime against the Titans.

In two playoff games this season, quarterback Patrick Mahomes has thrown for 615 yards and eight touchdowns while adding another rushing touchdown as he leads the third most efficient offense per Football Outsider DVOA metric of team efficiency (2nd in the pass and 14th in the run). The Chiefs are a predominantly an 11 personnel team (one running back, one tight end, three receivers) and use the personnel grouping 79% of the time.

Andy Reid is off the Bill Walsh west coast offense coaching tree, although he never completed a coaching stint in San Francisco. Instead, he coached under Mike Holmgren (49ers quarterback coach in the 1980s) in Green Bay on a staff that included Steve Mariucci and Jon Gruden. As such, his offense blends a lot of west coast concepts together with the air raid that Patrick Mahomes is more accustomed to playing, as well as a variety of packaged plays that allow them to take full advantage of the speed they have in players like Tyreek Hill and Sammy Watkins.

Defending the key concepts

Chiefs vertical concepts

The Chiefs like to run a lot of 3x1 trips to get their speed matched up on linebackers and slower safeties over the middle. A common concept they like to run from this is either three or four verticals. The Chief’s explosiveness out of 3x1 formations can be a simple blend of route combinations, but the key factor that makes them so dangerous to defend is speed, especially if they get a 1-on-1 matchup against a slower defender.

Slower is a relative term here. Adoree Jackson is the Titans defender here, and he ran a 4.42 40-yard dash at his combine. Tyreek Hill is the middle slot in the Chiefs trips formation; he ran a 4.24 40-yard dash at his combine. Hill runs right past Jackson, who has no safety help over the top.

The Titans are in man coverage, so the other corner Tremaine Brock runs with the #3 crosser. The opposite safety Kenny Vacarro drops to the middle of the field with #3 as well, leaving Jackson alone with Hill. Mahomes drops the pass over Jackson to Hill for the touchdown.

The Chiefs had fits running their 3x1 against the Chargers this season, who run a similar scheme defensively to the 49ers and may provide a blueprint for defending the Chiefs explosiveness.

Here the Chiefs are rerunning three verticals from the trips to the left. The Chiefs are in a single high coverage shell with the down safety opposite the trips on the hash. He’s looking for any vertical or deep crosser that comes his way.

The middle vertical is run by receiver Demarcus Robinson (No. 11). Jaylen Watkins (No. 27) is the safety on the opposite hash. It picks up the vertical in his zone, allowing safety Rayshawn Jenkins to run over the top of the middle vertical by Robinson.

Mahomes tries to fit the pass in over defender Desmond King (No. 20) in the slot covering Robinson, but Jenkins comes over the top and closes the throwing window that Mahomes has. He times it perfectly and jumps in front of Robinson to intercept the pass.

The 49ers have made adjustments to their defensive passing scheme this season with the addition of former Broncos defensive coordinator Joe Woods. In it, they’ve implemented more 2-high coverage shells and disguised 2-high and 1-high safety looks. And have largely had success when defending against 3x1 verticals.

In the NFC Championship Game, the 49ers showed a similar defensive look to the Chargers play above. However, they didn’t reveal their true intent pre-snap. After the snap, safety Jimmie Ward buzzed down to the strong hook zone from his 2-high position to cut the crossing route. This immediately removed the deep crosser from quarterback Aaron Rodgers’s progression, and he immediately looks to the left to throw the seam.

Cornerback Emmanuel Moseley, playing a “zebra ⅓” technique (midpoint #1 and #2 receivers), falls off the curl route on the outside by #1 as soon as he sees Rodgers come back to the seam by receiver Geronimo Allison. Rodgers throws, but the pass is behind his receiver due to linebacker Fred Warner being in the throwing lane, and Moseley jumps the route and picks off the pass.

Chiefs offense in the red zone vs. 49ers 1-high and 2-high defense

In the red zone, the 49ers are also likely to see their share of 2x2 or 3x1 formations from the Chiefs offense. The Chiefs have a variety of concepts they can run, and among their favorites are smash and double stick nod.

In week three of 2018, the Chiefs had their way with the 49ers defense, hanging 35 points on them by halftime. They lost by a final score of 38-27 when a potential comeback was cut short by an ACL injury to quarterback Jimmy Garoppolo.

For most of 2018, the 49ers defense was prone to playing a single-high coverage in the red zone and if often burned them. One way to beat a single-high safety in the red zone is to run two verticals at him and let him declare which route he’s going to cover. Once the safety commits, the quarterback should then come back to the open vertical. Mahomes does that here on a nice adjustment to a common West Coast Offense staple, the stick/flat concept.

On stick/flat, the stick route is usually run to a depth of around five yards before the receiver or tight end plants and turns outside away from the interior defenders. Here, the Chiefs are in a YY double tight end formation to the left and the two receiver side to the right.

Both the inside tight end Demetrius Harris (No. 84) and Tyreek Hill (No. 10) in the right slot are running the stick nod routes. Mahomes looks right for Hill and gets safety Tarvarius Moore to commit to that side. As he does, Mahomes resets and looks left, finding Harris wide open for the touchdown.

One adjustment the 49ers are likely to make against 2x2 (or even 3x1) in the red zone is to play “cover-6 skate.” This past preseason, the 49ers and Chiefs met for a week three preseason game. In that game, the 49ers committed to a 2-high coverage defense inside the red zone.

The Chiefs are running a split concept from 3x1 with a dagger/seam concept from the trips and a swirl/flat concept to the right. The 49ers are in a 2-high safety shell that that morphs into cover-6 skate post snap. The coverage allows the defense to blanket all the receivers.

If the defense can cover for the few seconds needed for the play to develop, the pass rush can get home and flush Mahomes from the pocket, like they do here, or force him into errant or off-target throws.

Chiefs sail/flood vs. single-high coverage

Single high defenses are prone to giving up big plays if the offense floods one side of the field with deep, intermediate, and shallow routes because of the stress it puts on the curl/flat defender. If he sinks under the deep sail route, the quarterback can hit the flat route. If he covers the flat route, the quarterback will hit the sail route.

Against the Chargers in week 11, the Chiefs are running a 3-level sail concept with a flat route, a sail/intermediate route, and deep go route.

The Chargers are in a cover-3 defense. The combination of the intermediate and flat routes puts the curl/flat defender in conflict. He stays shallow to the flat so Mahomes hits the sail route behind him for a big gain.

In 2018, the Chiefs hit a variant of this play for a big gain to tight end Travis Kelce against the 49ers in an obvious coverage bust. The difference here is the Chiefs used play action to draw the linebackers up just enough to get Kelce behind them.

Kelce angles his route across the field to the hash like he’s running a crossing route but cuts back out into the open zone between the hash and numbers.

No defender dropped into that weak hook zone, and instead, both the hook and curl/flat defenders closed on the back out of the backfield, allowing a big to Kelce.

This season, with the coverage adjustments the 49ers made, they were better able to play those flood concepts with both single high and two high safeties. The primary ways they played opposing team’s flood concepts were with Cover-3 soft sky and simple Cover-2.

In Cover-3 soft sky, the idea is to keep the same Cover-3 principles intact by keeping the down safety in the box to play the run but also having the ability to Cover 2x2 verticals. The free safety shades weak and leans toward the weak side doubles while the strong safety drops with any slot vertical from the strong side.

Here, safety Jaquiski Tartt is the down safety to the strong side of the field. The Panthers are running a sail from the tight end position and a clearing route on the outside that pulls the corner deep. In a regular cover-3, this could be highly problematic. But instead of playing normal curl flat responsibility, he plays a “soft sky” instead of a normal spot drop hook zone and drops over any vertical from the interior.

With safety Jimmie Ward shaded to the boundary, Panthers quarterback Kyle Allen is probably thinking he has an easy deep completion on the sail route to the far side of the field. Tartt sinks under the sail route, though, and Allen is forced to hit his check-down underneath.

Another way to play the flood concepts we’re likely to see is by the defense playing a disguised cover-2 that looks like single-high pre-snap. Defensive coordinator Robert Saleh has been doing a fantastic job this year calling these coverages, and they’ve paid off in huge moments.

Here the Steelers have a speed out outside with a corner route behind it from a two-receiver stack. Underneath, they flood that side with a shallow crosser from the opposite side of the formation. The 49ers are showing a cover-3 shell with single deep safety and cornerback Richard Sherman playing off coverage, indicating that he might bail to a deep third zone.

At the snap, the Sherman keeps eyes in the backfield, looking to see where Mason Rudolph is going to throw. The safeties rotate to a 2-deep shell, and the far safety runs with the corner, removing it as an option. Rudolph comes down to the quick out and thinks he has the easy completion, but Sherman breaks on the pass, forcing an incompletion.

How the Chiefs offense can frustrate the 49ers defense

Run-pass Option

The Chiefs use the run-pass option 19% of the time this season, more than any other team in the league. It can be a frustrating thing to have to defend with all the speed the Chiefs have across the offense.

One of their favorites is tagging a backside glance or slant to the outside zone. RPO slant-arrow is a quick hitter.

The play above is a glance route where the receiver widens the corner with his stem (angle out) before cutting inside like he would on a slant. The play is designed to hit somewhere 10-plus yards down the seam.

Another variation is an RPO with a wheel tagged to the tight end out of the backfield.

Mahomes is reading the safety who walks down to the line of scrimmage. If he plays the run, Mahomes knows he has the wheel open. If he plays the wheel, he can give to the running back.

Mahomes throws to tight end (former 49ers tight end) Blake Bell as the safety looks to plug the B-gap on the run. Mahomes pulls the pass and throws to a wide-open Bell who walks in for the touchdown

Screens and motions

The 49ers defense struggled with screen passes this year. Add in the motions and shifts that Chiefs use, and they could be in a for long day.

The Chiefs might look at what the Rams did to the 49ers in week 16 for clues on the how the 49ers defended screens in that game. The Rams hit several for big gains and the Chiefs have their own arsenal of screens they’ll try to throw at the 49ers defense like they did in 2018.

Out of 3x1, the Chiefs like run verticals that pull the defense downfield while the screen develops behind the line of scrimmage. If they aren’t running verticals out of 3x1, they’ll tag other route concepts that laterally stretch the defense to open up the middle of the field as they do in the second clip with a stick concept that clears the middle of the field.

With their motions, they like to get defenses looking in all directions. In this play, they use orbit motion with three separate fakes to different personnel, discombobulating the defense and picking it apart.

Mahomes executes a run fake, a fake to the decoy swing route to his left, another fake to the decoy swing route to his right, before just dumping the ball off to tight end Travis Kelce for a nice gain. The defense is trying to watch each potential ball carrier, and as a result, they are slow to react to the play developing right in front of them.


This is not at all a comprehensive breakdown of what the 49ers can, should, or will do versus the Chiefs. For that reason, you should also check out Scott Geelan’s piece that further explores how the single high coverages are employed by various teams that had success slowing the Chiefs down.

In the next piece, we’ll briefly look at the ways the 49ers offense can and will have success against the Chiefs defense.