‘Boston Blue’ Recast Shock: Why Andrew Terraciano Was Replaced as Sean Reagan!

If you tuned in for the highly anticipated premiere of Boston Blue on CBS last week, you might have done a double take – one familiar face from Blue Bloods looked a little different.

In a surprising move, Mika Amonsen has stepped into the role of Sean Reagan, the youngest son of Danny Reagan, a character originally portrayed by Andrew Terraciano throughout Blue Bloods’ impressive 292-episode run.

Naturally, fans had questions. Why the change after so many years of seeing Andrew in the role?

Co-showrunner Brandon Margolis opened up about the decision in an interview with Variety, explaining that the choice wasn’t about replacing Andrew’s legacy, but about ushering in a new era.

“We love Andrew and the work he did over the years on Blue Bloods,” Margolis said. “It really came down to the fact that we’re telling a new chapter in both of their lives. It’s not just Sean who’s joined the family business – Danny is now a father to a cop, and that’s a dynamic we’ve never explored before.”

Margolis added that the creative team saw this as a chance to refresh the character and bring in a different perspective:

“There were all these new storytelling lanes to explore. It felt like the right time to introduce a new performance with new energy – to help dramatize that change. It’s the same character, the same relationship, but with a completely different tone.”

He also praised Mika Amonsen’s take on the character:

“We love what Mika has brought to Sean – this mix of vulnerability and determination, a real desire to prove himself. It’s been amazing to see it come to life.”

With a fresh face and a deeper father-son storyline ahead, Boston Blue is already carving out its own identity – while still honoring the family legacy that made Blue Bloods a TV favorite for over a decade.