The topline on Miami's 2025 defense reads like a familiar story of decline: run defense EPA/play swung from -0.068 (7th) in 2024 to +0.043 (27th) in 2025, the third-largest year-over-year drop in the league behind only the Giants and Bills. But that number is a smear that hides the actual pathology. Miami's run defense didn't collapse everywhere. It collapsed in one specific place — between the guards — and opponents have already tilted their play sheets to hunt it.

Table of Contents

1. The overall collapse
2. Where the leak actually is
3. Opponents have noticed
4. First down is now a free square

The overall collapse

Start with the wide angle. Miami's defense as a whole went from -0.022 EPA/play allowed in 2024 (9th) to +0.088 in 2025 (27th). The run side specifically slid from -0.068 (7th) to +0.043 (27th) — a +0.111 swing that ranks 3rd-worst in the NFL year over year, trailing only the Giants (+0.151) and Bills (+0.150).

That's the setup. It's also where most recaps stop. The interesting part is what's driving it.

Where the leak actually is

Split Miami's run defense by where the ball carrier crossed the line and the two halves of the front tell completely different stories.

The perimeter actually got better — Miami's edges are giving up -0.052 EPA/play on runs off tackle and end this year, a real improvement on 2024. It's the interior that fell out. Runs between the guards swung +0.211 EPA/play year over year, from one of the best marks in football to the worst: Miami's +0.096 EPA/play allowed on interior runs in 2025 is the worst in the NFL by a nose over Atlanta (+0.096 vs. +0.096, MIA edges out to No. 32 on the fourth decimal), with Buffalo (+0.078) a clear step behind.

This is a two-gap problem in the most literal sense possible. Everything that isn't the A- or B-gap is holding up fine. Everything that is has caved in.

Opponents have noticed

If you were an offensive coordinator staring at that split on tape, you would call the same play until someone stopped you. And that's more or less what has happened.

The league-average share of run plays that attack the interior (guard or middle) in 2025 is 51.9%. Against Miami, opponents have run interior on 60.1% of their carries — about 8.3 percentage points above league average, and the 3rd-highest rate faced by any defense in football, behind only Houston (61.4%) and Seattle (61.1%). That's on 454 rush attempts, so it isn't a small-sample quirk.

Two defenses being attacked interior at a higher rate is not a defense of Miami — it's evidence this is a broader league pattern of hunting soft interiors. What makes Miami's version dangerous is the combination: the third-most-interior-heavy diet in the league, absorbed by the interior defense giving up the most EPA/play in the league. Houston and Seattle are being run at inside because they're big, and offenses are choosing violence; Miami is being run at inside because it works.

First down is now a free square

The downstream cost shows up on first down, where Miami used to make life miserable and now doesn't.

That's a 0.162 EPA/play swing on first-down runs and a 3.5-percentage-point jump in explosive-run rate. In 2024, opposing offenses that ran on first down against Miami were essentially wasting a play; in 2025, they're gaining leverage on it. Roughly one in every 6.6 first-down carries against the Dolphins this year has gone for 10+ yards.

That's the compounding piece. A defense that can't win first down on the ground doesn't get to play the down-and-distance game it's built for — the pass rush works from behind the sticks, coverage gets simpler, everything downstream is easier. Miami has lost that leverage.

What this pins the story on

The perimeter is fine, the interior is the worst gap in football, opponents have already adjusted their play-calling to attack it at the third-highest rate in the league, and the first-down consequences of that are showing up in explosive-run rate.

Whether the fix is personnel (interior D-line, off-ball linebackers filling A-gaps) or scheme, it's a narrower problem than "the defense is bad."