The midseason finale of Boston Blue finally mentioned Tony Terraciano's character, Jack Reagan, but is he one of the upcoming Blue Bloods cameos after Donnie Wahlberg's other onscreen son was already recast? During the Friday, December 19, episode of the CBS series, Danny (Wahlberg) revealed that Jack was doing Doctors Without Borders in Africa, which was a nod to Terraciano, 25, attending medical school to earn his Doctor of Medicine. "It's important to us that we keep the universe alive.