Ferguson sold the Portuguese to the Spanish giants for a world record of £80 million.
But the player is being linked with a move away from Madrid this summer due to personal problems at the club.
“I don’t think it’ll happen but I would like to think it would”, Ferguson told Man Utd’s website.
“We’d be talking incredible amounts of money now. What do you think his value would be? He’s never injured. When does he ever miss a game? Who could afford him?”
