Jeff Hafley is leaning on a familiar face as he begins shaping the Dolphins in his image. Miami is expected to hire Sean Duggan as its new defensive coordinator, a move that reunites the first-time NFL head coach with a longtime collaborator he trusts implicitly.
Duggan’s rise has closely mirrored Hafley’s for years. Their professional paths first crossed at Ohio State in 2019, when Hafley served as the Buckeyes’ co-defensive coordinator and Duggan worked as a graduate assistant. When Hafley left Columbus to take over at Boston College, Duggan followed, coaching linebackers from 2020 through 2022 and later adding a co-defensive coordinator title in 2023. That partnership continued into the NFL when Hafley joined Green Bay, with Duggan coming aboard first as a defensive assistant in 2024 and then as the Packers’ linebackers coach this past season.
Now, Duggan takes the biggest step of his career. At just 32, he’s poised to become a first-time NFL defensive coordinator, charged with implementing a scheme that should be fully aligned with Hafley’s philosophy after nearly a decade of working side by side. The familiarity between the two should ease the transition, but the task awaiting them in Miami is anything but simple.
The Dolphins struggled defensively in 2025, finishing in the bottom third of the league in both points and yards allowed. The secondary, in particular, is in flux, with Miami among the league’s worst teams in interceptions and multiple cornerbacks headed toward free agency. The pass rush also lacks depth, leaving plenty of work to be done on that side of the ball.
How the roster ultimately comes together remains to be seen, but Duggan will be entrusted with maximizing it. For Hafley, bringing along a trusted lieutenant provides continuity and comfort as he steps into his first NFL head coaching role. For Duggan, it’s a defining opportunity to prove he’s ready to lead a defense at the highest level.
