Mika Amonsen will replace Andrew Terraciano, who played Sean Reagan throughout the 14-season run of "Blue Bloods."

Blue Bloods' viewers are finally getting an explanation for why Donnie Wahlberg’s character, Danny, moved in the 'Boston Blue' spinoff

Donnie Wahlberg Celebrates ‘New Chapter’ at First 'Boston Blue’ Table Read originally appeared on Parade. Donnie Wahlberg celebrated the official start of the Blue Bloods spinoff, Boston Blue, by sharing a photo from the first table read.