From Aldridge's piece on NBA.com:
The Lakers, with a payroll already projected in excess of $83 million next season, would only be able to offer Nash an exception starting at $3.09 million for next season. It’s unlikely Nash would take that, so a sign-and-trade deal would be a more realistic possibility.
The Lakers do have a viable starting point guard they could send Phoenix in such a deal, Ramon Sessions, who became an unrestricted free agent after surprisingly opting out of the last year of his contract. Forwards Jordan Hill and Matt Barnes are also free agents.