Miami Dolphins defensive coordinator Sean Duggan has been working with head coach Jeff Hafley since 2019. Duggan was a graduate assistant at Ohio State in 2019 while Hafley was their co-defensive coordinator and defensive backs coach.
When Hafley went to Boston College to be their head coach from 2020-23, Duggan followed and spent three seasons as a linebackers coach. Duggan was promoted to co-defensive coordinator and linebackers coach in 2023.
The coaching relationship continued when Hafley went to Green Bay to be the Packers’ defensive coordinator, while Duggan started as his defensive assistant there in 2024, then in 2025 worked again as a linebackers coach. Now with Hafley the main man in Miami, he once again brought Duggan making him his right-hand
man.
The young coordinator spoke with South Florida reporters Thursday and tipped his hand on where he will be location-wise during games and how the defense will be ran in-season. He said, “I'll be wherever Jeff wants. He's going to call it, so just being his eyes either on the field or up in the booth.”
In his third NFL training camp, Duggan discussed topics with media ranged from the progress and development of returning players such as Chop Robinson, Jason Marshall Jr. and Zeek Biggers, as well as how several rookies are performing.
Regarding Robinson, Duggan said, “I think first he changed his body. I mean, the way this guy worked in the offseason with our strength and conditioning team and then by himself, I think that's showing up now.”
Duggan continued with, “I mean, he's completely transformed the way he looks. And then not that he had a bad attitude when he got here, but he's embraced playing the run, playing early down. I can't say enough of how much that guy's worked. You're seeing it pay off, which is great.”
When asked about the utilization of Robinson and Biggers, the coordinator said, “Yeah, it's depending on the call and the situation, I hate to say that. It's not a cop out answer, it really is, and those guys are doing great. We put a lot on the d-line as far as our front variation and lining in different places to make it challenging for the offense.”
Duggan praised both players telling media, “those two have done a great job, Zeek in particular being able to play across the line.”
Moving to the secondary, Duggan spoke Marshall, telling the press, “ I think he's done a great job. Kind of similar to what I was saying about Chris, just the poise he plays with. He's a very even keel guy, which I think you need to be out there. He loves to challenge people and get his hands on guys. The guy can run. It's nice to see him using his hands, not staying blocked. He's done a great job.”
Sticking in the defensive backfield, the Dolphins have a first round pick in cornerback Chris Johnson, and Duggan likes what he sees, saying, “the thing that's impressed me the most about him is just the poise he plays with out there. For a rookie, the moment's never too big. He always seems under control. I think I kind of said this in the spring is he learns from his mistakes. He understands how he's going to be attacked and very rarely does he make the same mistake twice.”
Moving to the coordinator’s area of expertise, being a former linebacker, he spoke about Miami’s trio of rookies in the room, Jacob Rodriguez, Trey Moore and Kyle Louis.
Duggan discussed the rookie defensive trio, saying, “I tell you, they're all doing a great job. We've thrown a lot at the linebackers. We've put a lot on their plate. To handle the amount of information and install we've done is pretty impressive from those three, and they're just getting better.”
Adding to his assessment of the young linebackers, Duggan added, “They're starting to get a feel for the calls. When you get a feel for the calls, you can start looking across the ball and be like, okay, well, what am I getting? Is there a cut split here? You know, is this tight end a little deeper? Is the guard sitting back in his stance? So when you start to get more and more comfortable with the calls, you can start to pick up on what the offense is doing.”
He then said, “But I think just those three have done a great job. Just their attitude every day, right? Their willingness to learn. And what I love is they just go out there and play, man. Just go play fast. We'll correct the mistakes. We'll correct everything that we need to schematically, but just go cut it loose out there.”
Duggan was also asked about his veteran linebackers in Tyrel Dodson and Jordyn Brooks as he spoke about the duo saying, “I think the veteran leadership's got to push the message of the head coach and then teach them things that have worked for them.”
He then said, “Whether it's routine, whether it's recovery, whether it's how to learn the playbook, how to study film. Everybody's different, but I think just if they can teach like, hey, this has been my process because they've earned the right to teach that, right? They’re vets and they've had a lot of success in this league, but just teaching them how to go about being a pro because those guys are still learning that.”
Duggan and his defense will face a live opponent next week in a joint practice with the Washington Commanders before the teams face off in their opening preseason game on August 14.
This article originally appeared on Dolphins Wire: Dolphins coach details most Chris Johnson's most impressive trait
