Blue Bloods viewers are finally getting an explanation for why Donnie Wahlberg's character, Danny Reagan, relocated to Boston for the show's upcoming spinoff. News broke on Wednesday, July 9, that Mika Amonsen is taking over the role of Wahlberg's youngest onscreen son - who was originally played by Andrew Terraciano on Blue Bloods - for

Mika Amonsen will replace Andrew Terraciano, who played Sean Reagan throughout the 14-season run of "Blue Bloods."Though Donnie Wahlberg is the only member of the core Blue Bloods cast set to return for the long-running series' first spinoff,

Danny Reagan’s youngest son Sean will look a little different when he appears alongside his dad on CBS’ upcoming drama series Boston Blue. Mika Amonsen has been cast as a series regular opposite Donnie Wahlberg on the Blue Bloods offshoot,