While fans would love to see Tom Selleck reprise his iconic role as Frank Reagan, introducing him into Boston Blue too early could ultimately do more harm than good. The upcoming Blue Bloods spinoff already faces a tough challenge winning over an audience still grieving the loss of a show many believe ended too soon.
If Selleck returns right away, fans might focus on the familiar instead of giving the new cast a fair chance. That could overshadow talented additions like Ghostbusters star Ernie Hudson, who’s stepping in as the new family figure at the heart of the story. Giving Selleck the spotlight again too soon would rob both Hudson and the series itself of the opportunity to establish something fresh and distinct.
At its core, Boston Blue is about Danny Reagan carving his own path. If Frank keeps appearing through cameos or phone calls, that growth disappears, and the series risks feeling like Blue Bloods Season 15 a continuation CBS has already chosen to move past.
For Boston Blue to truly succeed, it needs room to stand on its own. Selleck’s return should be saved for later 
used as a powerful, earned moment once the new show has built its own identity and emotional foundation.