Just How Good Is the Denver Broncos' Defense?

For most of his career in Indianapolis, Peyton Manning led the Colts to great success despite struggles on defense.

Manning’s defensive teammates in Denver are now in a position to flip the script.

The Broncos defense ranks seventh in points allowed per game (18.5) and second in yards allowed per play (4.2). On offense, they're tied for 12th in points per game (25.0) but rank last in yards per play (3.7).

It is probably not wise to count Manning out, but Denver will not need him to be the old Manning, given the strength of its defense.

The Broncos are currently second this season in Adjusted Defensive Net Expected Points (NEP), after ranking 11th last year.

This should continue to be one of the best units in football, taking some of the burden off the 39-year-old quarterback.

No-Fly Zone

The key to winning in the NFL, contrary to what is often said on TV, is passing and stopping the pass. On both sides of the ball, passing efficiency correlates with victory at a significantly higher rate than rushing efficiency, so fortunately for Denver, its strength on defense is stopping opposing quarterbacks.

The Broncos are second in net yards allowed per pass play (4.3), and lead all defenses in Adjusted NEP per pass.

The pass defense has picked up where it left off last season, as Denver ranked first in net yards per pass attempt (5.3) and seventh in Adjusted NEP per pass in 2014.

The Broncos success against the pass starts up front, where Denver ranks sixth with a 9.5% sack rate. DeMarcus Ware has led the way here, with two sacks, six quarterback hits and an additional seven hurries, per Pro Football Focus’ charting data.

Von Miller is off to a hot start as well, adding a sack, a pair of quarterback hits and nine hurries.

Denver’s secondary has looked good also, led by solid cornerback play.

Aqib Talib is one of three players in the NFL with two interceptions, and has allowed three receptions for 32 yards on nine targets and 63 coverage snaps (per PFF).

Talib’s 0.51 yard-per-coverage snap rate is 13th among NFL corners, but only second on the Broncos.

The leader is not actually 2014 Pro Bowler Chris Harris, but the second-year player Bradley Roby. The 31st overall pick in the 2014 draft is tied for fourth at the position with 0.26 yards per coverage snap, and has allowed two catches for 11 yards on three targets.

Harris, who was second in yards per coverage snap last season, does not have as good charting numbers through two games this season (ranking 44th in yards per snap, while allowing eight catches for 71 yards on 10 targets), but remains one of the best corners in the game.

Denver has intercepted four passes to give them an unsustainably high 7.0% interception rate. This leads the league, but should regress closer to the league average of 2.4% (turnovers are notoriously random).

Still, this has consistently been one of the best units in the NFL, and there is no reason not to expect this to continue.

Solid on the Ground

While rush defense is less important than pass defense, this hardly means it is unimportant.

Denver has not been as stout here, but their rush defense has hardly been a weakness. After ranking in 10th Adjusted Rushing NEP per carry in 2014, the Broncos are 11th this year.

In terms of yards per carry, Denver does not look as strong, as it has allowed 4.3 and ranks 24th.

Yards per carry can be misleading, though, particularly in small samples, as it can get skewed by only one or two long carries.

If we take away Jamaal Charles 34-yard touchdown run in Week 2, Denver’s yard-per-carry average drops to 3.72, and the Broncos move up 11 spots in the rankings.

In addition to our expected point rankings, another better way to judge rushing efficiency is success rate, the percentage of plays that yield positive expected points.

Denver’s opponents have 20 “successful” plays on 52 rush attempts, giving the Broncos a 61.5% success rate (this would have ranked seventh in the league last year).

This bodes well for Denver, considering that success rate correlates with victory and itself better than yards per carry.

Looking at the big picture, while Manning’s dominance is no longer a given, his defense looks like something he can count on, and this should help the Broncos remain among the AFC’s elite.