Porto striker Hulk is a surprise target for Manchester United. The News of the World says United boss Sir Alex Ferguson is an admirer of the Porto star and wants to strengthen his forward line as he bids for a fourth successive Premier League title.

The Brazil international has a clause in his contract that says he cannot be released for less than 100m euros, but sources at the Portuguese club say a realistic offer of around £20m would see Hulk leave the Estadio do Dragao at the end of the season.

"The big clubs in England have been in contact," said the player's agent Teodoro Fonseca. "They have asked for details about his contract situation but any decision about his future rests mainly with the directors of Porto.

"I am calm about the situation and so is the player because he has an excellent future. I think we could be discussing a move in April or May."

Hulk made his Brazil debut against England in November and now has two caps. He is likely to be named in his country's World Cup squad.

He got his nickname because of his stocky appearance and his likeness to actor Lou Ferrigno, who played the comic book hero.

"Hulk would be a good investment for United," said a Porto source.

"He has the quality to be a superstar in England and his club will have no choice but to take a big offer for him very seriously."