Sean McDermott’s defense let down the Bills again in the NFL Playoffs

With a Super Bowl trip on the line, the Buffalo Bills defense once again could not contain Patrick Mahomes and the Kansas City Chiefs.

Another season, another playoff exit for the Buffalo Bills at the hands of the Kansas City Chiefs.

The Bills have bested the Chiefs in four consecutive regular season meetings, but Kansas City has shattered their Super Bowl dreams in four of the last five seasons. Sunday’s thrilling 32-29 win in the AFC Championship marked the latest chapter of playoff heartbreak for Buffalo. While head coach Sean McDermott has led undoubtedly the best run of success the Bills have had since their four straight Super Bowl trips in the 1990s, they’re also in the same conference as Patrick Mahomes and Andy Reid, who are inevitable.

The common theme in all of these Bills losses has been the capitulation of McDermott’s defenses. While injuries to key players like Matt Milano, Tre’Davious White, Taylor Rapp, and Christian Benford have played a significant role over the span of their defeats, the difference in regular season vs. postseason performance has been staggering.

Here’s a comparison of their drive outcomes:

Bills defense against the Chiefs in their four regular season wins

13 punts
9 touchdowns
9 turnovers (7 interceptions, 2 fumbles)
5 field goals
2 turnovers on downs
1 missed field goal

Average points per game: 19.5
Points per drive: 2.00

A total of 14 scoring drives allowed out of 39 total possessions, good for a scoring rate allowed of 35.9%, nearly 10 percent below Kansas City’s average scoring rate since 2021. In the regular season, Buffalo has been able to keep the Chiefs’ point totals low and score enough on offense to vanquish Mahomes.

Then the playoffs happen...

Bills defense against the Chiefs in their four playoff losses

17 touchdowns
7 field goals
6 punts
3 end of half kneel-downs
3 end of game kneeldowns
2 turnovers (both fumbles)
1 missed field goal

Average points per game: 34.75
Points per drive: 3.56

For the record, the Detroit Lions led the NFL in points per drive at 3.09 in 2024.

If you’re keeping score (pun intended), the Bills have allowed 24 scoring drives out of 39 possessions. Take out six kneel-downs and it’s 24 out of 33, for a scoring rate of 72.7% and a touchdown rate of 51.5%. The Chiefs have never had to punt more than twice in any of these postseason meetings and have averaged 34.75 points in their wins. Sunday’s game marked Kansas City’s season high in points scored (32) and tied for a season high in first downs (28).

Buffalo’s defense has ranked no worse than 12th in FTN’s DVOA efficiency metric over the past five seasons. When the Chiefs won the 42-36 overtime classic in the 2021 season, the Bills were No. 1 by DVOA. It simply hasn’t mattered come playoff time.

Bills’ playoff defense is a problem vs other QBs, too

Incidentally, not playing Patrick Mahomes has not always been the magic potion for McDermott. In the 2022 Divisional Round loss to Joe Burrow and the Cincinnati Bengals, the Bills allowed 27 points on five scoring drives out of nine possessions, which means they’ve conceded an average of at least 3 points per drive in all of their last five playoff losses.

Josh Allen and the Bills offense have largely done their part to try and topple the Chiefs dynasty. Unfortunately, there has been close to no help from the defensive side of the ball.

While it’s clearly easier said than done to contain the Chiefs offense, it’s not completely impossible to at least slow them down. Sean McDermott’s defenses have been repeatedly unable to provide even minimal resistance, and the sample size of failures is large enough to wonder if that will ever change.

(All stats provided by Stathead)