The 2015 Denver Broncos won a Super Bowl championship on the backs of the best defensive unit in franchise history. Sorry Orange Crush, but this unit ran a gauntlet unlike any other in NFL History taking down three of the top four offenses that year. Offenses that included the like of Tom Brady, Cam Newton and Ben Roethlisberger. It was nothing short of historic.
So what happened?
The narrative all offseason was that all the Broncos needed was a mediocre offense and they’d have a shot to defend their title.
Well, their offense improved marginally, yet here we are looking at their 8-6 record and wondering if they will miss the playoffs.
The discussions and arguments have been going round and round on this site for days now. Blame Trevor Siemian? Blame the offensive line? Blame the running backs? Even blame the defense?
As is true of most hotly contested debates, it’s a little truth sprinkled over every point. numberFire broke things down in a way that just tied all of those truths together in a neat little bow for us fans. It was too good not to break down and share.
According to them, the 2015 unit was the best defensive unit in all of football using their Net Expected Points (NEP) metric. Not only that, they were twice as good as the next best defense. They are again the top ranked unit in football, but not quite by as large of a margin.
The big change has been the run defense.
Opponents are averaging almost a yard more per carry -- 3.3 to 4.2 -- this season than they were against the Broncos last year. With more yards gained on the ground on earlier downs, opponents are seeing more manageable third downs than they were in 2015.
Last year, only 19 percent of opposing third downs came with three or fewer yards to go. This year, that’s gone up to 27 percent.
While the third down conversion percentage is only a few percentage points higher this year, the extra yard in the run game is resulting in longer drives and more time of possession for the opposing team.
First comes from time of possession. Last season the Broncos defense kept opposing offenses to the fifth-lowest time of possession per drive at 2:30. This year, though, they’re more in the middle of the pack, ranking 13th in opposing time of possession per drive at 2:38. Those eight seconds per drive take away time for a Broncos offense that’s still struggling to score points -- something we’ll get to in a bit.
It also leads to a few more yards per drive. While the Broncos still lead the league in that aspect, they’ve gone from allowing 22.5 yards allowed per drive to 25.5. And with the 10th-worst average starting field position for a defense, those few extra yards can sometimes mean the difference in getting into field goal range or punting.
Field goals allowed have been one of the biggest differences on defense. Last season, the Broncos were ninth in field goals allowed per drive, but this year they’re 21st.
If you are still with me, you are starting to see how higher time of possession is leading to longer drives and more field goals.
Dan Pizzuta, the author of this piece at numberFire, then ties these slight regressions from the defense into how the offense has played its role in the 8-6 record. In 2016, the offense ranks 26th in NEP as opposed to 28th last season. A slight improvement, however, its merely slight. They are 23rd in passing and 28th in rushing using numberFire’s NEP rankings. Not good.
Those shorter drives and plethora of 3 and outs is leading to fantastic field position by opposing offenses.
Most of the time an opposing team only needs to gain two first downs to be near field goal range, which leads to points. Points the offense is no longer able to score on a consistent basis.
While it’s not all on the defense, not even close, it is interesting how sharp that razor thin edge is between winning and losing in the NFL. For the Broncos, it equates to just under a yard per run over the course of fourteen games.