The Portuguese star moved to Real Madrid last summer.
Sir Alex Ferguson believes that the door is not closed for a possible return to Manchester United for Cristiano Ronaldo, who was transferred to Real Madrid in the summer window for a record £80million.
Real Madrid crashed in the Round of 16 of the Champions League for the sixth consecutive season when they lost out to Lyon 2-1 on aggregate, and there is a lot of pressure from the Spanish press to see the Real Madrid player live up to their transfer price tags.
Ferguson is aware that playing for the Spanish giants is a lot more difficult than playing for Manchester United.
“Cristiano knows the value of Manchester United. That’s the thing. What the players have got here is protection. They come to training every day and there is nobody here to disturb them," he told The Sunday Express.
“I don’t think Real Madrid is an easy club to play for. There is a circus attached to it. There are often loads of fans and an intensive media always filming them.”
Even though the Portuguese winger has only been in Madrid for a little under a year, Ferguson will not rule out Ronaldo returning to Old Trafford in the future.
“You would like to think that one day he will come back, but you never know. I don’t think he will stay at Real Madrid for life or anything like that.
“There will be other challenges and he is that type of player who welcomes them.”Become a fan of Goal.com USA's Facebook fan page for all the latest news and insight into everything related to the beautiful game