In Saturday’s early game, something’s gotta give

I’ve been going extra-nerdy this week, referring to the division-round opener as an exercise in Newtonian physics. The irresistible force meets the immovable object. Or, as NBC SportsTalk producer Ricky Diamond put it yesterday while we were prepping for the show, it’s the 49ers hosting the 45ers.  Yes, in each of the past three games,…