If NBC ends up canceling Blacklist in its entirety, it would have 97 episodes (both main and spinoff) for off-network syndication reruns. (Assuming season 4 of Blacklist is a regular 22-epsiode season).
But NBC doesn't give a damn about syndication, they don't own the show and don't get a cent from reruns. So WB (Who I think owns it) will need to fight, and I think they will.
My guess is that Blindside will be thrown out, like Revolution, big hit one year, dead the next.