Fergie cannot go on forever and Anderson fears United will never be the same again when Ferguson finally calls it a day.
"Manchester United is Alex Ferguson. When he leaves, the club will lose 30-40%, so much depends on him," he told the Grande Área television program in Portugal.
"He is a father to all the players, a very respected person and when he retires the football world will really feel his loss.
"He always helped me and I have a great affection for him. He lives for training and always wants to know how his players and their families are."