Where Did Dolphins Go Wrong on D-Line?

The Miami Dolphins have had issues throughout their roster so far in a wildly frustrating start to the 2025 season, but there may be no more disappointing group than the defensive line.

And when they face the Los Angeles Chargers on Sunday, they'll get a painful reminder of how, in part, things went awry with that position group.

The Dolphins have gotten to this point, where the defensive line — and we're excluding the edge defenders as part of this discussion — is getting pushed back on a regular basis in the run game and generating very little in terms of pass rush.

The Chargers, meanwhile, have gotten really good production from Da'Shawn Hand after they signed him away from the Dolphins as a UFA this offseason and even more from Teair Tart, who was with the Dolphins last summer but couldn't even make it to the final cuts to the 53-man roster.

Regardless of how you feel about Pro Football Focus grades, it's kind of staggering that Tart is ranked as the No. 1 interior defensive lineman through the first five weeks of the 2025 regular season.

The Dolphins, meanwhile, don't have an interior defender graded higher than 97th (that being rookie fifth-round pick Jordan Phillips) and rookie first-round pick Kenneth Grant is tied for 117th out of 119 IDLs graded.

Moving past subjective grades, the stats tells an even more eye-opening story.

This is the impact Tart and Hand have made so far this season compared to what the Dolphins have gotten from their six-member interior defensive line of Zach Sieler, Benito Jones, Matthew Butler, Grant, Phillips and fellow rookie draft pick Zeek Biggers.

In five games, Tart and Hand have combined for 1 sack, 5 tackles for loss, 4 quarterback hits and 3 passes defensed.

The Dolphins' entire interior defensive line group has combined for 0.5 sack, 2 tackles for loss, 3 quarterback hits and 1 pass defensed.

Again, that's two players versus six.

PROVEN TALENT OUT, UNPROVEN TALENT IN

So would the Dolphins defensive line automatically be much better had the Dolphins not released Tart last summer and/or re-signed Hand this offseason (and he got a one-year, $2.75 million deal from the Chargers, so it's not like the cost is exorbitant)?

It's probably not quite that simple, but it's definitely clear that the Dolphins are paying the price for going with a youth movement up front.

It's way too early to make any definitive judgments on any of the three rookie defensive linemen, but it's fair to say the performance hasn't been up to par.

It's obviously more notable when it comes to Grant, not because of his PFF grade, but because he was the 13th overall selection.

And while it always was unrealistic to expect him to come in and dominate from the start, it was absolutely fair to expect better results.

Using PFF as a gauge, Grant has four games where he got a grade below 40, the one exception the Week 2 game against New England where he was given a 63.3.

By comparison, 2019 13th overall pick Christian Wilkins, who was playing on a team turning the roster over every week fared much better, with no grade worse than a 51.5 through his first five games and two above 74 in Weeks 4-5.

Of course, this is where we need to point out that Wilkins had much more seasoning than Grant coming into the NFL as a four-year starter at Clemson, but the difference still is pretty jarring.

While the rookie growing pains were to be expected, the dramatic drop in production from Zach Sieler has been startling.

In a Pro Bowl-caliber season, Sieler had 10 sacks, 13 tackles for loss and 19 quarterback hits in 2024.

After signing a contract extension this summer, Sieler through five games in 2025 has zero sacks, two tackles for loss, one quarterback hit.

Yikes.

Defensive coordinator Anthony Weaver said a couple of weeks ago that Sieler perhaps was trying to do too much to help out and make up for the rookies alongside him, and maybe there's something to that.

It's also fair to point out that after playing with Wilkins for four years and then having Calais Campbell next to him, it's a different ballgame lining up next to unproven and green talent.

And this brings us to the departure of Campbell, a blow that may have been underrated at the time he signed with the Arizona Cardinals. And it's of course painful to watch him continue to produce with his original team, though not re-signing him doesn't look like as big of a miss as not keeping either Tart or Hand because Campbell has said he wanted his career to go full circle.

As it stands, Sieler and Jones are the only two interior defensive linemen back from last year, with the three rookies and Butler replacing Campbell and Hand, along with part-time players Matt Dickerson and Neil Farrell.

The roster moves here clearly were a case of taking a step back in the short term to hopefully take several forward in the future — and the strategy will pan out if Grant and Phillips continue to develop and become bona fide NFL starters.

But probably nobody expected the short term change to be this painful.

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