Sporting Lisbon striker Ricky van Wolfswinkel's contract carries a €22 million buyout clause.

Manchester United assistant manager Mike Phelan has confirmed their interest in the young Dutchman, who only moved to Sporting last summer from FC Utrecht.

Van Wolfswinkel's agent, Louis Laros, has confirmed the buyout clause in the youngster's current deal.

"Incidentally, this clause was initially higher," Laros told Voetbal International. "It was one of the contentious negotiating issues."