It’s always tough to make a one-to-one comparison between coaching staffs in the NFL. From year to year, so much changes about team personnel that it’s sometimes tough to pinpoint what changed philosophically or what changed out of necessity.
Take the Dallas Cowboys for instance. Last year’s starting cornerback tandem of Stephon Gilmore and Daron Bland have played zero snaps for the team in 2024. Can a change in the way the secondary schemes be tethered to a necessary change with Trevon Diggs return and a fifth-round rookie in Caelen Carson playing opposite him? Or is it more about Mike Zimmer implementing what has always been a much different philosophy when it comes to coverages than his predecessor Dan Quinn?
So far in 2024, there’s been a major difference between the way the secondaries have been deployed. And while it was expected for their to be a learning curve for the secondary players as Zimmer’s coverages are notoriously complicated, it’s been a dramatic shift in results.
Last season, the Cowboys were equally as likely to deploy their secondary in Cover 1, man-to-man with a centerfield deep safety, as they were in Cover 3, where the two corners play zone along with said deep safety.
This year though, Zimmer greatly cut back on the man-to-man philosophies. Cover 1 calls have dropped from 34% of snaps in 2023 to just 17% through the first four weeks of 2024. 2-Man calls, man-to-man corners with two deep safeties, have disappeared completely, going from 3% to 0% accotding to data colleted by Football Insights.
Cover 3 calls have risen from 30% of all defensive calls to 38%, but the biggest riser has been the use of Cover 6. That’s where half the field plays quarters coverage (four-deep zone) and the other half of the field is in an underneath zone.
Are the changes working?
Last year the Cowboys ranked fifth in defensive dropback EPA (expected points added) at -0.06 and seventh in defensive passing VOA (value over average). EPA measures on a per play basis how well a defense does in preventing the expectation of a score for the offense at -3.3%.
VOA is a metric that takes into account game situation and opponent strength to measure how well a unit is doing. A negative rating means the opponent is seeing less success than the average opponent.
In 2024 those numbers have plummeted. Dallas currently ranks 18th in defensive dropback EPA, allowing opponents to increase their chances of scoring with each pass at 0.041. They’re also 21st in pass-defense VOA at 12.3%.
Things have gotten decidedly worse, but the question is are these issues due to other factors, or the philosophy? Everything about the Dallas defense is worse than it was a year ago, from their run stopping ability to their pass rush. So is the coverage calling a result of trying to compensate for what’s happening in the front seven or a symptom of the same core issue?
