"The Cowboys defense was bad in 2025" is a take everyone already has. The number worth staring at is more specific: Dallas allowed +0.167 defensive EPA/play, the 4th-worst mark by any NFL defense since 1999 — a 27-season window that covers roughly 850 team-seasons.

And the failure had a shape. This wasn't a broad, evenly-distributed collapse. It was one very specific thing going catastrophically wrong.

Table of Contents

1. The headline: 4th-worst since 1999
2. Where the damage happened: the deep ball
3. The worst deep-ball completion rate
4. The eleven bombs
5. What it added up to

1. The headline: 4th-worst since 1999

Only three defenses in the entire EPA era (1999–2025) surrendered more expected points per play than the 2025 Cowboys:

Within 2025, the Cowboys' pass defense was the second-worst in the NFL by EPA/play allowed through the air (+0.221), trailing only the Jets (+0.253) and comfortably ahead of the third-worst Commanders (+0.201). On the ground Dallas allowed +0.095 EPA/play, which is bad but nothing like historic — it's the passing game that put this defense in the record book.

2. Where the damage happened: the deep ball

The pass_defense_depth table breaks pass EPA into behind-the-line, short, intermediate, and deep (20+ air yards). Here's Dallas in 2025:

Every bucket except behind-the-line ranged from mediocre to awful. But 1.02 EPA per play on deep throws was the 3rd-worst mark in the NFL in 2025, behind only Minnesota (1.08) and Pittsburgh (1.08).

3. The worst deep-ball completion rate

The most striking single number in this whole exercise is the year-over-year jump in deep completion percentage against Dallas:

The volume of deep shots taken barely moved — 70 to 66. What moved was the hit rate. Opposing quarterbacks completed 45.5% of their 20+ air-yard throws against Dallas, up from 31.4% the year before, while the Cowboys' deep-ball interception total fell from six to two.

That 45.5% is the highest mark against a Cowboys defense in any season the pass_defense_depth table records (back to 2011 for Dallas specifically). The nearest comparison in the last 15 years is 2020 at 45.9% — but that Dallas team faced 61 deep targets and gave up 0.68 EPA/play on them, a full third of a point less per play than 2025.

In other words: opponents didn't try to attack Dallas deep more often. They just connected far more often when they did, and every completion did more damage.

4. The eleven bombs

Dallas allowed 11 touchdowns on passes traveling 20+ yards in the air in 2025 — the second-most in the NFL, one behind Chicago (12), and ahead of San Francisco, Pittsburgh, Detroit, and Atlanta (all 8–9).

The biggest individual deep-ball games against Dallas, by receiving yards on 20+ air-yard throws:

The Giants — a two-win offense in most weeks — put up 212 deep receiving yards and three touchdowns across their meetings, mostly on Nabers and Robinson.

5. What it added up to

Dallas finished 7–9–1, scoring 471 points and allowing 511. The offense was fine — 471 points is a top-10ish scoring output.

Historically bad defenses usually get remembered as a whole-unit failure — "they couldn't stop anyone." The 2025 Cowboys were different.