Boston Blue cast shake-up: Not Andrew Terraciano, but this actor to play Sean Reagan in the Blue-Bloods spin-off

CBS caused a stir earlier this year when it revealed that Boston Blue, a spin-off of Blue Bloods, was in the works. Created by Brandon Sonnier and Brandon Margolis, the show shifts focus to Danny Reagan as he transitions from working at the NYPD to joining the Boston Police Department. Jerry Bruckheimer produces the show with Donnie Wahlberg, who brings back his role as Danny.

The network has scheduled the premiere for the 2025–2026 season. As fans gear up for the fall launch, buzz about the recasting of Sean Reagan has taken center stage. CBS announced on July 9, 2025, that Andrew Terraciano, who had played Sean for 14 seasons, wouldn’t be part of the Boston Blue cast.

Instead, Mika Amonsen, recognized for his performance in Thanksgiving (2023) and a guest role on Prime Video’s Reacher, now takes on the part. This change in casting suggests a shift in creative focus. The show skips lengthy backstories by starting Sean Reagan in the Boston PD setting, which creates a quicker connection and puts the spotlight on the father-son dynamic in a fresh setting.

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The decision to recast Sean Reagan reflects a shift in storytelling priorities

Andrew Terraciano’s departure may come as a surprise to long-time fans, but CBS appears focused on positioning Sean as a young officer already established in Boston.

The creative team reportedly wanted to streamline the narrative, making Sean’s presence in the department feel grounded from episode one. Mika Amonsen’s casting supports this, presenting a version of Sean that fits the spin-off’s tone and pace.

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Sean’s new role in the Boston PD sets the stage for fresh dynamics

Sean already has a job as a patrolman in Boston, so the show skips explaining any move from New York. Instead, it dives right into their daily routines.

Now, Sean and Danny can end up handling cases together. This opens doors to stories about police procedures and adds more emotional tension between them.

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The spin-off aims to preserve core family themes despite casting changes

Donnie Wahlberg’s character will remain central, and while the cast is increasing, familiar emotional anchors from Blue Bloods are expected to remain. Wahlberg recently mentioned that other Reagan family members could appear through calls or cameos, keeping the family component alive in Boston Blue. The goal appears to be a careful balance of new energy and old connections.

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New characters are being introduced to shape Boston’s world

Joining Wahlberg and Amonsen are Sonequa Martin-Green as Detective Lena Silver and Ernie Hudson as Reverend Peters, among others. Their inclusion reflects Boston Blue’s effort to build a more localized story—one grounded in Boston’s own policing culture and community dynamics. The introduction of the Silver family, in particular, proposes long-term character arcs that are independent of the original show.

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Boston Blue is scheduled to air in the original Blue Bloods time slot

CBS will air it on Fridays at 10/9c, a deliberate choice to carry forward the legacy of Blue Bloods without displacing its core audience. While the city and cast may differ, the network is positioning the show as a direct successor.

By skipping origin stories and placing Sean and Danny in their new environment right away, Boston Blue signals its intent to move at a quicker pace. The dynamic between father and son, now as fellow officers, will likely be central, with plenty of space to explore how their bond evolves under new pressures.

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As Boston Blue nears its premiere, it presents a combination of continuity and change: familiar characters, new challenges, and a city that brings a different rhythm to police work.

Whether Mika Amonsen’s portrayal of Sean wins over loyal fans remains to be seen, but CBS appears committed to developing the Reagan saga while preserving what made it resonate for 14 seasons.