CBS has officially greenlit Boston Blue, a Blue Bloods spin-off centered on Donnie Wahlberg’s character, Danny Reagan, and his son Sean. However, longtime fans may be surprised to learn that Andrew Terraciano, who played Sean Reagan across all 14 seasons of the original series, won’t be reprising the role.

Mika Amonsen will play Sean Reagan in the 'Blue Bloods' spinoff, 'Boston Blue,' a role previously played by Andrew Terraciano.

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