I'd never seen anything in the broadcasts that would indicate a problem between them, only heard of rumors of an incident years back (which must have been true), some dust up about Rod not being professional, ready for the game or something.
Mario is good enough with play by play. Rod brings nothing to the game for me, same old dry talk, no insight or (intentional) humor.
Yea, I'm really curious what could be so bad to spark a physical fight between a couple of 50+ year old men.