Is it possible? Sure, just about anything is. But General Petraeus has never struck me as someone who's particularly interested in political convenience - his interest is in making sure the job gets done, and if he can't do it, then he'll let you know and point you in the direction of who can. His record speaks for itself in that regard.

Meantime, both the FBI and senior officials have been rebutting what you suggest, and there's been no evidence yet that supports the theory. Unless anything else turns up, I think this is probably going to wind up being a dead end in which the president will barely even be involved.