Ronald Koeman believes Romelu Lukaku may have to leave Everton to realise his full potential.
The Toffees manager has admitted he does not know if Lukaku will stay at the club beyond next summer, after the prolific Belgium striker agreed in August to remain for another season.
And Koeman thinks Lukaku, who has scored seven goals in 11 appearances for Everton this term, has the ability to play for Barcelona.
"I gave him confidence and he has himself recognised that it was good for his development to play another year at Everton," Koeman told Belgian newspaper HLN.
"There is a very good contact and appreciation between us. What after this season comes, no one knows.
"If Romelu was to play at Everton until the end of his career, I know he has left something (behind). His potential is greater and higher than Everton, as a final destination.
"Patrick Kluivert was also a striker who was quite young in the picture and had a fantastic career. Eventually Kluivert played for Barcelona, which could happen with Lukaku.
"He is potentially a great striker, one who is only 23 years old. I think Lukaku is quite complete. He can hold a ball and be a target man and, because he is tall and physically strong. You can play directly with the long ball."