The Buffalo Bills have built their roster to beat the Kansas City Chiefs. It’s natural. Most teams across the NFL — especially those at the top — have tried in one way or another to figure out how to hang with the Chiefs.

For the Bills specifically, two crushing losses to the Chiefs in 2020 highlighted areas Buffalo needed to improve to take the next step in contention. The 38-24 loss in the AFC Championship Game caused head coach Sean McDermott to claim there was “still a gap between where we are and where they are.”

“It’s not just one answer that solves that problem,” McDermott added. Buffalo will get a chance to see if they got the answers right this offseason when they travel to Kansas City for Sunday Night Football. 

With an offense that was one of the league’s best in 2020, the Bills looked to improve the defense, specifically the pass rush. Buffalo used first- and second-round picks on pass rushers in the hope to improve a unit that was arguably the weakest on the roster last season.

It’s early in the 2021 season, but the initial results have been better than most could have expected. After the defense disappointed a bit by ranking just 12th in DVOA during 2020, the unit ranks first after four weeks of 2021.

Buffalo just put up one of the best single-game defensive efforts of all time and the gap between the Bills and the No. 2 defense in DVOA is bigger than the gap between Nos. 2 and 27. There aren’t opponent adjustments in those numbers yet and the opponents have not been great, but blowouts and dominant performances are signs of a great team.

But of course, the likes of the Steelers and Vikings offenses are much different than what the Bills will face against the Chiefs, a team they couldn’t quite figure out last season. In his two games against Buffalo, Patrick Mahomes completed 50-of-64 passes (78.1%) for 550 yards (8.6 yards per attempt), with five touchdowns and no interceptions. He averaged 0.36 EPA per dropback and positive EPA on 69.7% of his dropbacks, according to Sports Info Solutions. He faced pressure on just 28.8% of those dropbacks.

During the first game in Week 6, the Bills were an early adopter of how many teams tried to defend the Chiefs in 2020. They sat back in a two-high structure, gave the Chiefs light boxes to run against, and rushed four to keep all other resources in pass coverage. Mahomes and the Bills stayed patient. The quarterback took the open short passes for an average depth of target of 5.9 yards past the line of scrimmage. The Bills rushed four on 91% of their pass snaps, but pressured Mahomes just 26.5% of the time, per SIS.

The lack of pressure with the front four caused the Bills to be more aggressive in the rematch. Buffalo gave more single-high looks to add an extra defender in the box against the run and the short/intermediate passes then used more post-snap rotation that got them back into split-safety coverages to play against the deep pass. Up front, the Bills rushed four 74% of the time and blitzed 21%.

Mahomes was still able to pick apart the defense focusing on the available short and intermediate throws (5.6 aDOT). The inability to get to Mahomes with four in the regular season meeting forced the Bills to blitz more and blitzing Mahomes hasn’t worked all that well for opposing defenses. In that game, Mahomes went 6-of-8 for 59 yards and two touchdowns. But even without the blitz, Mahomes went 22-of-28 with 69% positive play rate against Buffalo’s four-man rush.

Both meetings against Mahomes and the Chiefs featured a defensive game plan that diverged from their typical defensive tendencies.

TimePre-snap Single HighPre-snap Two HighPost-Snap Single HighPost-Snap Two High4-man RushBlitz
2020 Full Season44%51%40%48%68%31%
Week 629%68%59%26%91%0%
AFC Championship Game55%41%38%46%74%21%

So far in 2021, the Bills have relied more on that four-man rush. Buffalo has rushed four 81% of the time, which is the fifth-highest rate in the league. The biggest difference, though, is they’re actually getting pressure while doing so. When the Bills rushed four in 2020, they created pressure just 33.4% of the time which ranked 24th in the league. So far in 2021, the Bills have created pressure on 50.9% of their four-man rushes, which is the second-best rate in the NFL per Sports Info Solutions, behind only the Carolina Panthers.

That four-man rush has been good, but like the Panthers, the Bills have been able to create pressure by manipulating the pre-snap looks, especially on third downs. Against the Miami Dolphins in Week 2, the Bills loaded the line against a condensed formation from the Dolphins. At the snap, linebacker Matt Milano (58) looped into the A-gap while first-round pick Gregory Rousseau (50) dropped back into coverage. Milano created quick pressure that forced Jacoby Brissett out of the pocket. Rousseau dropped into the shallow middle zone and was able to rush to pick up the sack after Brissett tried to scramble.



Rousseau has played a big part in the increased pass rush productivity for Buffalo. The first-round pick has played 54.5% of the defensive snaps, which leads the team’s edge rushers and trails only Ed Oliver (55.8%) along the defensive line. Rousseau, so far, has been one of the best players at creating pressure off a four-man rush. Per SIS, he ranks 12th among defenders in pressure rate in those situations.

Pressure Rate on Four-Man Rush, 2021 (min. 50 pass rushes)

PlayerTeamPass SnapsPass RushesRush%Pressure%
Trey HendricksonBengals838096.4%22.4%
Micah ParsonsCowboys1025049.0%21.3%
Matt JudonPatriots594678.0%20.9%
Brian BurnsPanthers665786.4%20.4%
Maxx CrosbyRaiders124124100.0%20.2%
Joey BosaChargers5454100.0%18.8%
Khalil MackBears757093.3%18.2%
T.J. WattSteelers706390.0%17.7%
John Franklin-MyersJets737298.6%17.4%
Myles GarrettBrowns8484100.0%17.1%
Jadeveon ClowneyBrowns8383100.0%17.1%
Greg RousseauBills564987.5%16.3%
Quinnen WilliamsJets6262100.0%15.3%
Cameron HeywardSteelers9393100.0%15.2%
Javon HargraveEagles7272100.0%15.2%

The Bills have also rotated more on defense, keeping the pass rushers fresh. Rosseau, Jerry Hughes, Mario Addison, and A.J. Epenesa have each played at least 40% of the defensive snaps this season.

Buffalo has also put together an interior pass rush that has been able to get to quarterbacks. Oliver is 10th among defensive tackles in pressure rate on four-man rushes. He’s started to show off the quickness he was believed to have as a college prospect.



Justin Zimmer has been on the field for 47.7% of the defensive snaps after he played more rotational interior rusher last season. Zimmer, now in his age-29 season on his third team as an undrafted free agent, finished 2020 with seven quarterback hits on 29% of Buffalo’s defensive snaps and he’s worked his way into a bigger role in 2021. 

The pass rush is just one piece of the puzzle and it has helped the Bills become more aggressive in the secondary. Buffalo is a team that has played in more two-high pre-snap looks (their 57% ranks 12th) but they’re also rotating to more single-high coverages (47%) than they used last season.

Buffalo Bills Defensive Tendencies, 2020-2021

SeasonPre-snap Single HighPre-snap Two HighPost-Snap Single HighPost-Snap Two High4-man RushBlitz

Buffalo’s pre-snap looks and post-snap rotations have deterred opposing offenses from even attempting deep passes against the defense. Per SIS, the Bills have faced just four passes 20 or more yards past the line of scrimmage through four weeks. Opponents averaged -1.47 EPA per play on those four throws. Only seven other defenses have allowed better than -1.47 total on deep passes this season.

This also hasn’t been a defense that has been picked apart on short throws, either. Buffalo is also first is EPA allowed per play and fifth in positive play rate on throws that travel between 1-10 yards past the line of scrimmage.

Buffalo Bills Defense By Pass Distance, 2021

DistanceAttemptsEPA/Att (Rank)Positive Play % (Rank)
1-1069-0.43 (1)43.5% (5)
11-19190.04 (5)52.6% (8)
20+4-1.47 (1)0% (1)

The lack of deep passes has allowed the secondary to sit and pounce on throws to that part of the field and it’s where the combination of the pass rush and coverage has shined.

Take the two interceptions the Bills forced Taylor Heinicke to throw in the Week 3 matchup against the Washington Football Team. On the first, the Bills rushed four on a second-and-6 and while pressure wasn’t immediately created, the coverage held up and left Heinicke with few options. After he bounced around in the pocket, the quarterback thought he had an open Terry McLaurin, but Jordan Poyer patiently sat in his zone and jumped the route for the pick.



On the second, a third-and-12, the Bills did get pressure with the front four. As Heinicke scrambled out of the pocket, he forced a throw into traffic where both deep safeties were in position to pick the ball off. This time, it was Micah Hyde.



The cornerbacks have also held up well in coverage. Tre’Davious White is the featured player but both Levi Wallace on the outside and Taron Johnson in the slot currently rank among the top-20 cornerbacks in Adjusted Yards allowed per coverage snap, which accounts for touchdowns and interceptions.

All of these pieces will need to be on point against the Chiefs. Kansas City is no stranger to teams wanting to defend against the deep pass. It’s already happened against the Bills. Mahomes was more than willing to take the underneath options and move the ball that way. So far, Buffalo has been able to sit on those underneath throws and no teams have had success taking that path against them. The biggest difference is that pass rush. Getting pressure with four opens up the backend and the Bills have taken advantage of what that has meant with seven in coverage. It’s worked to this point.

It’s already been established the Bills are good in 2021 and a close win — or loss — might not tell us much more about the true talent level of the team. But the Chiefs continue to be opponents’ measuring stick game. The Bills had that in mind as they worked their way through improving the roster in the offseason. The lead-up has worked out exactly how Buffalo would have hoped. Now it’s time for the test.