I will touhgt that Nasr would get a drive because of his big sponsors. I think Grosjean's seat at Lotus isn't a shoe in. I can see Nasr at Sauber or Lotus next year. What happened to the roebels of Sirotkin, Sauber is promising a lot of drivers seats and then sell them to the highest bidder that can actually write over the bank cheque. 2nd driver at Sauber could be Guitterez, Nasr, Sirotkin, Chilton and V/D Garde. The guys who gets the seat has the biggest sponsor deal, Sauber have made i pretty clear with announcement of Ericsson that talent isn't their main concern but money is.
But I can't imagine Sauber ditching Esteban 1 year before the MexicanGP, with Claro and Telmax as big sponsors at the moment.