The 2025 Dallas Cowboys were one of the strangest teams in recent memory — not because of any single result, but because their two units looked like they belonged to different franchises.

Their offense finished 4th in the NFL in EPA per play at +0.097, behind only the Rams (+0.145), Bills (+0.138), and Packers (+0.122). Their defense finished 32nd — dead last — at +0.167 EPA/play allowed, about two hundredths of a point worse than the next-worst team, the Jets (+0.147).

That gap, on its own, is remarkable. What's genuinely unique is where that defense ranks against 25 years of history.

Table of Contents

1. A split the EPA era hasn't seen before: a 4th-worst-since-2000 defense
2. The mechanism: a deep-ball defense that fell off a cliff
3. What the gap means on the scoreboard

1. A split the EPA era hasn't seen before

Two different questions are getting asked here, and it's worth separating them before the numbers pile up. First: has a top-5 offense ever been paired with the single worst defense in its own season? Second, a much narrower question: has a top-5 offense ever been paired with a defense this bad in absolute terms, measured against every team since 2000? The answer to the first is yes, a handful of times. The answer to the second, as far as the data since 2000 shows, is no.

On the first question: since 2000, four other teams have paired a top-5 offense with the single worst defense in their own season — the 2002 Chiefs (1st-ranked offense, worst defense), the 2004 Chiefs (2nd offense, worst defense), the 2010 Texans (3rd offense, worst defense), and the 2015 Saints (4th offense, worst defense). So "top-5 offense, worst-in-league defense" is rare, but it has happened. The 2025 Cowboys (4th offense, worst defense) join that list.

On the second, harder question: ranking every defense since 2000 by EPA/play allowed, the 2025 Cowboys come out 4th-worst of any defense in the 26-year sample, behind only the 2020 Lions (+0.204), the 2008 Lions (+0.179), and the 2020 Texans (+0.170). None of the other four teams on the first list comes close to that territory. The 2010 Texans' defense — worst in its own season — ranks just 10th-worst all-time. The 2008 Broncos, whose 2nd-ranked offense wasn't quite worst-defense-paired that year, still had the 11th-worst defense all-time. The 2015 Saints' defense ranks 13th-worst all-time.

Nobody else in the sample combines a top-5 offense (in its own season) with a defense inside the all-time bottom five since 2000. That's the 2025 Cowboys' distinction.

2. The mechanism: a deep-ball defense that fell off a cliff

The collapse isn't the tail end of a long slide — it's sudden. Dallas's pass-defense EPA/play allowed and league rank, by season:

From 2021 through 2023 Dallas ran a top-7 pass defense every year, including the best in football in 2021. Two years later it's 31st of 32.

The specific failure point is the deep ball. Cowboys defense against targets of 20+ air yards, by season:

The 2021 unit held opposing quarterbacks to a 32.5% deep-ball completion rate and gave up 0.19 EPA per deep target. The 2024 group was still one of the stingier deep defenses in the league, at 31.4% and 0.47. In 2025 the completion rate jumped to 45.5% and the EPA cost more than doubled to 1.02 per deep target.

In three years, one of the best deep-ball defenses in the league became a bottom-ten deep-ball defense in the play-by-play era. That's the inversion driving everything else in this piece.

3. What the gap means on the scoreboard

An offense that plays efficient, +0.097-EPA/play football and a defense that surrenders +0.167 EPA/play sit on opposite ends of the league — and the pass game is where the offense actually did its best work. Dallas's passing offense produced +0.160 EPA/play in 2025, which trailed the Rams (+0.221), Packers (+0.242), Lions (+0.168), Patriots (+0.166), and Bills (+0.164), but ran well ahead of Seattle (+0.133), San Francisco (+0.125), Chicago (+0.089), and Indianapolis (+0.056) — a genuinely good, if not elite, passing attack by the league's own numbers.

None of that could offset a defense allowing +0.167 EPA/play, the single worst mark in the league. A team can be one of the more efficient offenses in football and still lose the argument on the scoreboard if its defense is giving back more value per snap than almost any unit in a quarter-century has. That's the practical version of the historical claim in Section 1: this wasn't a bad team with one hole, it was an excellent offense negated by a poor defense.

What this means

Deep-pass defense is genuinely volatile year to year — Dallas's own run from 1st (2021) to 4th (2022) to 7th (2023) shows how quickly a unit can move even while staying good. So some regression toward the mean next season should be the expectation, not a guarantee of collapse forever.

But regression doesn't erase what already happened. By the numbers in hand, the 2025 Cowboys paired a top-4 offense with a defense that ranks 4th-worst since 2000 and a deep-pass unit that ranks 9th-worst since 2006 — a combination nothing else in the sample matches. The diagnosis is specific: it's the deep ball, and it went from a strength three years ago to one of the worst in the league in one season. Whether Dallas actually fixes it is a separate question. That the problem is this identifiable is not.