Manchester United assistant manager Mike Phelan has admitted the club are keeping tabs on Sporting Lisbon striker Ricky van Wolfswinkel.
United have been linked with a move for the Dutchman after catching the eye at Sporting this season.
The 22-year-old, who joined Sporting from Utrecht in the summer, has scored six goals in his last six games to alert clubs from all across Europe.
A host of clubs were credited with an interest in Van Wolfswinkel prior to his move to Sporting and United No.2 Phelan has revealed they are long-term admirers of the Dutch international.
"We have obviously known Van Wolfswinkel for a long time," Phelan told Portuguese newspaper Record. "He is a young striker, very talented, who has been growing in the last few seasons.
"A club like Manchester United carefully follow many players all over the world."