Sporting Lisbon insist they have received neither an approach nor an offer for holding midfielder William Carvalho.
The midfielder, scouted extensively by Manchester United during David Moyes' reign, has a 45 million-euro release clause in his contract.
United, who will be managed by Louis van Gaal after the World Cup is over, have again been linked with the Portugal international.
However, Sporting chairman Bruno de Carvalho is adamant that there have been no talks about the 22-year-old, telling A Bola: "We haven't received any formal or informal proposals for any of our players."
Holding midfielder Carvalho was in Portugal's World Cup squad, starting the 2-1 win over Ghana, and has long been linked with a move.
United have signed from Sporting before, buying wingers Cristiano Ronaldo and Nani during Sir Alex Ferguson's reign, and Carvalho said his star players could realistically be lured away by offers from elsewhere.
He added: "Is a sale possible? Nothing is impossible in football."
Van Gaal has begun work on restructuring his midfield, bringing in Ander Herrera from Athletic Bilbao for 28.8 million pounds.
ESPN FC reported last week that United had been quoted 45 million pounds for Arturo Vidal of Juventus.