Highly-rated striker Yannick Djalo has put potential suitors on alert by turning down the offer of a contract renewal at Sporting.
The Portugal international is under contract with Sporting for two more years but is believed to have attracted the attention of several clubs, especially from Italy.
While Genoa have previously expressed an interest, it is Juventus who are now reported to be leading the chase.
Djalo's agent, Lionel Da Silva, refused to be drawn on the transfer talk but did indicate that his client would be keeping his options open after rejecting an extended deal.
"The interest of Juventus? I prefer not to comment on these rumours but I can say it is normal that a player like him arouses great interest," Da Silva told Tuttomercatoweb.
"In the past, there was a concrete interest from Genoa.
"Yannick still has a two-year contract with Sporting Lisbon, they offered a renewal but the player did not accept.
"I don't know if he can leave soon, it depends on if any offers arrive for him."