Calderon wants to retire Raul's No7 in recognition of his success with Real during his career and confirmed his plans last week.

However, it's unlikely Ronaldo's management will look kindly on the prospect of the Portuguese running around with anything but No7 on his back. The United star's multi-million pound merchandise rights lean heavily on his 'CR7' brand and the player, himself, admitted only this week he hoped to open a hotel known as 'CR7'.

Calderon said: "We do not know if he (Ronaldo) will join us. But Raul won't have to change his number. He is untouchable."