‘Boston Blue’ Shockingly Recasts Danny Reagan’s Son

The Reagan family may be returning to screens for Boston Blue, but at least one member will look a little different.

Ahead of the fall premiere of CBS’ anticipated Blue Bloods spinoff, Danny Reagan’s youngest son Sean Reagan has been recast in a shock cast shakeup.

After portraying the character in 292 episodes of Blue Bloods’ 293 episode run from 2010 to 2024, Andrew Terraciano will not appear as Sean in the upcoming offshoot. Instead, Mika Amonsen will take over the role opposite Donnie Wahlberg’s Danny Reagan, according to a Wednesday report from The Hollywood Reporter. The actor has previously been seen in Prime Video’s Reacher, Eli Roth’s horror flick Thanksgiving, and the Apple TV+ drama Pachinko.

Ordered to series in February just two months after the flagship show wrapped its 14-season run, Boston Blue is described as a “universe expansion” of the network’s long-running top drama Blue Bloods. The show follows Danny, a former NYPD officer, after he takes a position with Boston PD, where he is paired with detective Lena Peters, the eldest daughter of a prominent law enforcement family. His youngest son will seemingly follow him to Boston, where he becomes a patrolman for the Boston PD.

“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,” a synopsis for the character reads. “Danny’s decision to stay in Boston gives this father and son duo a chance to reconnect on a deeper level.”

Amonsen joins a cast that also includes Sonequa Martin-Green as Detective Lena Silver, Maggie Lawson as Sarah Silver, Marcus Scribner as Jonah Silver, Gloria Reuben as Mae Silver, and Ernie Hudson as Reverend Peters.

News of the cast shakeup came just a day after Wahlberg announced Tuesday that production on the show had officially begun. The actor shared a photo to his Instagram Stories showing a script Boston Blue’s pilot episode, written by Brandon Sonnier and Brandon Margolis and directed by Anthony Hemingway, on the table in front of him, as well as a name tag for his character. He wrote overtop the image, “A new chapter,” alongside a blue heart emoji.

Boston Blue is set to premiere on CBS this fall, appropriately airing in Blue Blood’s former 10 p.m. timeslot Friday nights. An exact premiere date hasn’t yet been revealed.