The Spanish paper claims the Champions League winning coach is using the same tactics he deployed in 1995 when he followed Eric Cantona to Paris to ensure the Frenchman was not tempted by any offers.
That season it seemed as if Cantona would leave following the infamous fly-kick he performed on a fan. Ferguson even brought in a psychologist to convince Cantona to stay and he might do the same with Ronaldo.
The Portuguese winger is currently on international duty where he may be exposed to contact from the Spanish club. Ferguson is ready to keep a close eye on his man and the coach will be looking to shoot down any potential threats by taking appropriate action.
It's going to be difficult for Real Madrid to try and convince the player but Calderon has in the past stated that he is ready to blow €90m to land the Old Trafford magician.
Manchester United have reacted angrily at Real's attempts to try and swoop for the player and the club has warned that they may report the La Liga side to the football authorities if they keep up their antics.
The Red Devils will not let the player move easily and they have always stated that he is not for sale at any price, whether or not Calderon gets the message and gives up on the midfield maestro remains to be seen.