In a word: bullshit.
At least according to my source in the GNR camp. The band, after all, is engaged in the careful planning of their own three-fifths reunion tour and NOBODY wants to risk Axl blowing out his voice, least of all Axl, who reportedly needs the cash that only a high-profile GNR reunion tour can bring.
A name I have heard bandied about: Myles Kennedy, he of Slash's Snakepit, ironically enough.
Kennedy, of course, has a bit of a rep for being such a problem solver, as when he stepped in to front Creed 2.0 AKA Alter Bridge, not to mention playing with Jimmy Page & John Paul Jones of Led Zep and singing on a couple Slash solo records.