Well, you're pretty screwed at the RB position if you can't get McCoy so I could make that deal first although I'm sure you could trade Marshall in a pinch for a top tier RB if need be. So, assuming you can solve your lack of RB depth, I'd pull the trigger and try to get Rodgers.
12 team auction (100$)
Foster $30, Charles $16, Tate 2$, Hillman 2$
Boldin 3$, Britt 5$ (drop), Gronk 9$
Tucker, K 1$,Tynes, K 1$
Jets D, 1$
Dwyer, D. Thomas
J. Nelson, Garcon, G. Tate