The 29-year old Spaniard left Ibrox for Villa in August 2008 and could be set for a Glasgow return if a deal can be sorted between the two clubs once Villa's new manager is appointed.
"I don't like talking about other people's players but I would be lying if I said I wasn't interested in a player of Carlos' quality," McCoist told the Daily Record.
"I'm back in the country now (after a scouting trp) so it's a matter of the clubs making contact and taking it from there.
"The managerial situation at Villa complicates the issue but as soon as they have made an appointment I'll be in touch to ask about Carlos' availability.
"It will be up to Villa's new boss to decide if he's willing to do business or not."