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,

Andrew Terraciano will not return as Sean Reagan in the spinoff, and Mika Amonsen will now take his place in 'Boston Blue'

CBS’s upcoming “Blue Bloods” spinoff has recast Danny Reagan’s son after the same actor played the recurring role throughout the original 14 seasons. Andrew Terraciano will not return as Sean Reagan in “Boston Blue” after appearing in nearly every episode across 14 seasons as the son of Donnie Wahlberg’s character,