Breaking Down Duke’s Biggest Defensive Vulnerabilities

The Blue Devils high-flying defense has wreaked havoc for opposing offenses, but there are areas where this unit can be exposed every week.

Sep 6, 2025; Durham, North Carolina, USA; Illinois Fighting Illini quarterback Luke Altmyer (9) runs during the first quarter against the Duke Blue Devils at Wallace Wade Stadium. Mandatory Credit: Zachary Taft-Imagn Images | Zachary Taft-Imagn Images

Duke is entering a bye week in the midst of their three-game winning streak that has featured impressive performances on both sides of the ball. There has been a solid mix of the offense and defense excelling at various portions during this win streak, which has led to both units finding success consistently.

While there are definitely positives to acknowledge, there are discussions that have to be addressed, specifically pertaining to the Blue Devils' defense.

Sep 27, 2025; Syracuse, New York, USA; Syracuse Orange running back Jaden Hart (22) is tackled by Duke Blue Devils defensive end Kobe Smith (18) in the fourth quarter at the JMA Wireless Dome. Mandatory Credit: Mark Konezny-Imagn Images | Mark Konezny-Imagn Images

With Duke off this week, this is a good time to analyze and deep dive into some of the issues with the Blue Devils' defense. Let's take a look at some of the difficulties this unit is facing every week.

Struggling to get off the field on third downs

The defense's primary job is to get the ball back to the offense, which is the primary source of scoring points. Although Duke's defensive unit has been fantastic at achieving that goal by creating turnovers, stopping opposing offenses on third down has been a work in progress this season.

Sep 20, 2025; Durham, North Carolina, USA; North Carolina State Wolfpack running back Hollywood Smothers (3) is tackled by Duke Blue Devils running back Anderson Castle (4) during the fourth quarter at Wallace Wade Stadium. Mandatory Credit: Zachary Taft-Imagn Images | Zachary Taft-Imagn Images

On the season, the Blue Devils' defense is allowing their opponents to convert 42.8% of their third downs, ranking 87th in the country.

It has become an even more significant issue over the last three weeks, as teams during that stretch have converted on 45.9% of their third downs. If this trend continues, Duke is going to struggle against the more formidable opponents in their conference.

Sep 6, 2025; Durham, North Carolina, USA; Duke Blue Devils defensive end Kobe Smith (18), cornerback Kimari Robinson (5) and linebacker Luke Mergott (34) bring down Illinois Fighting Illini wide receiver Hank Beatty (80) during the second quarter at Wallace Wade Stadium. Mandatory Credit: Zachary Taft-Imagn Images | Zachary Taft-Imagn Images

This issue is even more prevalent at home, as Duke is allowing opponents to convert on third downs in 48% of those instances. After the bye, the Blue Devils host Georgia Tech, which is efficient on those downs, moving the chains 44.8% on third downs.

Sep 24, 2022; Lawrence, Kansas, USA; A general view of a Duke Blue Devils helmet against the Kansas Jayhawks during the second half of the game at David Booth Kansas Memorial Stadium. Mandatory Credit: Denny Medley-Imagn Images | Denny Medley-Imagn Images

Pass coverage

Duke's front four masks a myriad of issues in the secondary. To be fair, the Blue Devils' corners and safeties are relatively young and inexperienced, but that is where opposing offensive coordinators are devoting their game plans. If teams can protect their quarterback, this secondary can be picked apart.

Sep 20, 2025; Durham, North Carolina, USA; North Carolina State Wolfpack linebacker Sterling Dixon (25) celebrates North Carolina State Wolfpack quarter back Will Wilson's (10) touchdown in the fourth quarter against the Duke Blue Devils at Wallace Wade Stadium. Mandatory Credit: Zachary Taft-Imagn Images | Zachary Taft-Imagn Images

According to PFF, Duke owns a 66.9 coverage grade, which ranks 97th in the country. This is telling when evaluating the roster and how they grade out in coverage.

Per PFF, there are only two players on the defense who own a coverage grade higher than 77.5, and that is freshman safety Andrew Pellicciotta and edge rusher Vincent Anthony Jr. Not great when a team's primary pass rusher is the highest-graded player in coverage through six weeks.

Sep 6, 2025; Durham, North Carolina, USA; Duke Blue Devils defensive end Vincent Anthony Jr. (7) celebrates with safety Terry Moore (1) after a touchdown against the Illinois Fighting Illini during the third quarter at Wallace Wade Stadium. Mandatory Credit: Zachary Taft-Imagn Images | Zachary Taft-Imagn Images

Duke's defense is an overall strong unit, but this pass defense is worrisome when considering the level of competition in this conference.