Ricky van Wolfswinkel's agent has denied having any contact with Manchester United.
The 22-year-old Dutch international only joined Sporting Lisbon from Utrecht this summer.
But the highly-rated forward has followed this up with four goals in four starts for the Portuguese giants.
Manchester United are now reported to be one of those keeping close tabs on him.
But his agent Louis Laros insists there has been no contact with any clubs.
"Ricky is very well in Sporting and very happy with the club, the city and the supporters," Laros told Abola.
"For him everything is perfect, for me not it is not a suprise this rumour but I have not spoken with anybody.
"It is normal the kid is linked with other clubs because people watch the Portuguese Liga and as always club scouts check on the best men and today Ricky is one of the best forwards."