A-Rod ain't moving to SS, he's been out of that position far too long to change back and is adequate defensively at 3B. Some combination of Nunez/Nix will play SS. I could see starting Nunez and replacing him late with Nix for defense since Nunez is so iffy on defense. I think Nix gets the nod from Joe.
Jeter sure isn't going to quit after a great season where he led MLB in hits....maybe if he had 3 bad seasons in a row, but not now. His replacement will be a downgrade.
Guys like Granderson suck against good pitching, so he isn't a valuable post-season player, A Jeter can adjust.
I'd call Cano's poor performance just a bad stretch in a small sample, as he was Bonds like a few weeks ago.
A championship worthy team can replace a jeter type player.