Where Did the Dolphins Defense Come Up Short?

If it already hadn't been established that the Miami Dolphins took a significant step backward on defense in 2025, there should be no doubt left after the rough outing against the Cincinnati Bengals last Sunday.

Along with giving up a season-high 45 points, the Dolphins allowed more than 400 total yards for the fifth time this season, albeit the first time since the Week 6 game against the Los Angeles Chargers.

The Dolphins now rank 19th in the NFL in total defense, and if this holds up it would be their worst showing in that statistical category since 2020 when they were 20th. But that 2020 defense made up for giving up yardage by taking the ball away, forcing an NFL-high 29 turnovers.

Yes, the Dolphins did have a nice run defensively during the four-game winning streak, holding the Buffalo Bills, Washington Commanders, New Orleans Saints and New York Jets to 13, 13, 17 and 10 points, respectively, but a couple of points need to be made here.

The first is that, like it or not, that wasn't exactly murderer's row the Dolphins faced after the Bills, particularly since none of the Commanders, Saints or Jets played with their opening-day starting quarterback.

The second is that the Dolphins feasted on takeaways in those four games, with three against the Bills and Jets and two against the Commanders and Saints. And if you don't think takeaways are big, the Dolphins have a 5-1 record this season when they finish with two or more takeaways but are 0-7 when they fail to force a turnover.

The bottom line is the defense simply hasn't been good enough, much like the entire team.

So what are the biggest reasons?

THE BIG ISSUES

Too young?

The Dolphins consciously wanted to get younger in 2025 after a few years of bringing in veterans to fill gaps, and there's a lot of merit to that strategy. There's also a downside.

And that downside is growing pains, which isn't just a cliché but a fact of life in the NFL.

With few exceptions, you can count on rookies and other young players having to learn on the job, which means there will be mistakes made early on that maybe won't happen later.

With their youth movement, the Dolphins wound up making extensive use of a lot of rookies on defense, starting with the three defensive tackle draft picks — Kenneth Grant, Jordan Phillips and Zeek Biggers.

And there we had Jason Marshall Jr. and Dante Trader Jr. in the secondary, not to mention second-year player Chop Robinson at the edge defender position.

The rookies absolutely have shown potential and could become key pieces moving forward, but the fact remains the performance was uneven at times in 2025, and that should have been expected.

Too much turnover?

This is turnover, singular, as in too many changes.

Through injuries but mostly departures, the Dolphins had only three 2024 opening-day starters on defense back with the team this season, and it's simply another fact of life that many new faces equals many challenges.

For one thing, the entire secondary was different and the two players who wound up starting the most games, Jack Jones and Rasul Douglas, weren't even on the roster until July and August as they were brought in after injuries hit the position, most notably the torn ACL that sidelined Kader Kohou early in training camp.

That shouldn't have been the biggest factor, and it probably wasn't.

“I think whatever we assemble as a group defensively, we need an opportunity to grow earlier," defensive coordinator Anthony Weaver said this week. "We need these people to be brought together earlier than they were. A lot of the guys that we ended up playing with either got here at the start of training camp, were kind of hurt in training camp, missed some of camp; so a lot of the growth we were trying to do as a defense occurred early in the season. When you combine that with the youth movement we were trying to make, that’s what’s going to happen early. I think eventually it started to click for all of them in terms of what the expectation and what we were trying to get done, but we need to start to get that ball rolling earlier than August.”

Not enough high-talent?

The Dolphins do have their share of quality players on defense, starting with Jordyn Brooks having a really impressive season at linebacker and continuing with Zach Sieler and Minkah Fitzpatrick, but do they have enough?

Or do they have enough who have performed at a high level often enough?

And if they didn't, was it a player issue (like inconsistency) or was it a coaching issue (like scheme)?

The young players very well might become high-end NFL starters at some point, but what realistically was their level of consistency as rookies?

And some of the free agent pick-ups maybe didn't perform quite up to hopes or expectations, whether it be safeties Ashtyn Davis and Ifeatu Melifonwu, and maybe the Dolphins could have gotten more week-in, week-out impact from big-name players like Bradley Chubb, Jaelan Phillips before he was started and Sieler, among others.

Whatever the ultimate reason, the defense wasn't good enough in 2025.