The Reagan family in the new Blue Bloods universe series this fall, Boston Blue, is going to look a bit different: one of Danny’s (Donnie Wahlberg) sons has been recast.

Mika Amonsen has joined the cast in the series regular role of Sean Reagan, CBS announced on Wednesday, July 9. Throughout the 14 seasons of Blue Bloods, through the series finale, the character was played by Andrew Terraciano.

For the new offshoot, Danny’s youngest son has relocated to Boston to start a new chapter as a Boston PD patrolman. Sean committed himself to pursuing his family’s legacy but wanted to do so on his own terms, which meant joining a department outside of his hometown. Danny’s decision to stay in Boston gives this father and son duo a chance to reconnect on a deeper level.

Boston Blue is a universe expansion of CBS’ long-running top drama and is taking over Blue Bloods‘ former time slot, Fridays at 10/9c this fall. In this new drama, Wahlberg reprises his role as NYPD Detective Danny Reagan as he takes a position with the Boston PD. Once in Boston, he is paired with Detective Lena Silver (Sonequa Martin-Green), the eldest daughter of a prominent law enforcement family.

The news of this recasting comes just two days after Wahlberg posted a photo from the table read for the series’ premiere on Instagram. Pictured was the pilot script’s cover page, along with “A new chapter” and a blue heart.

In addition to Wahlberg as Detective Danny Reagan, Martin-Green as Lena Silver, and Amonsen as Sean Reagan, Boston Blue also stars Maggie Lawson as Sarah Silver, Marcus Scribner as Isaiah Silver, Gloria Reuben as Mae Silver, and Ernie Hudson as Reverend Peters.

Boston Blue is produced by CBS Studios in association with JBTV. Brandon Sonnier and Brandon Margolis are showrunners and executive producers. Jerry Bruckheimer, KristieAnne Reed, and Wahlberg also serve as executive producers.

Boston Blue, Series Premiere, Fall 2025, Fridays, 10/9c, CBS