Coach Max Allegri is pushing for a revolution in midfield, as Pirlo was released on a free transfer to Juventus and the club is seeking a left-sided player.
"I read various names in the newspapers, but I have no idea who the mysterious Mister X could be. Besides, I can play in that left midfield role too..." Ambrosini told the Gazzetta dello Sport.
"We certainly need a replacement for Pirlo, even if someone with his characteristics would be impossible to replace. His absence will be felt on the field and in the locker room.
"There are players who can turn a team from normal to great. Andrea is one of those players. I started playing with him way back in the Italy Under-18 squad. He is unique."