Manchester United midfielder Anderson has predicted the club will lose "30-40 per cent" of their performance level when Sir Alex Ferguson retires.
Anderson joined the club in a big-money move from Porto back in 2008 and has revealed his current manager is a father figure to the players and is worried about the affect his departure will have on the club.
"Manchester United is Alex Ferguson. When he leaves, the club will lose 30-40%, so much depends on him," he told Grande Area television 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."
The 24-year-old Brazilian has struggled with injuries recently - making just 10 Premier League appearances in the 2011-11 campaign and two so far this season.
Ferguson, 70, took over the managerial reigns at Old Trafford on November 6, 1986 and has led the club to a host of trophies including 12 Premier League titles, five FA Cups, four League Cups and two Champions League crowns.