Manchester United legend Eric Cantona fears Wayne Rooney's top-flight career could be over within five years.
Cantona feels Rooney needs advice
Rooney, 20, is already a key player for United and England but Cantona is worried about his lifestyle.
He told the Daily Telegraph: "Rooney can be the best in the world at 25 if he knows you need to train hard, go to bed early and be careful what you eat.
"But he could also be out of the best teams, out of England, out of the best 100 players. Completely out."
Cantona feels Rooney needs advice now to ensure the longevity of his career.
He added: "This is very, very important. All the best players in the world knew all the time these kinds of things are very important.
"I am sure (United boss) Alex Ferguson is very strong and will help. Rooney is still young.
"But somebody needs to say it to him. The last time I saw him I wanted to say it but I saw him only quickly."
The former France international, 39, points at Robbie Fowler as an example of a teenage talent who has not fulfilled his full potential.
He said: "Fowler was so good at 18, and four, five years later, at 23 or 24, finished, not even playing regularly for England, not even for the best teams. Finished.
"Completely. Out. Why?
"Clubs should ask why this kind of player is out. They say in England it is very difficult because of the media pressure. But it is not more difficult than in Italy, Spain or Brazil."