Udinese have turned down a bid of 35million euros from an unnamed club for Alexis Sanchez.
The Chile international has reportedly attracted widespread interest across Europe following a string of impressive performances in Serie A this season.
Manchester City and Inter Milan are among those to have been heavily linked with the 22-year-old, although Udinese have refused to reveal who made the offer.
Club president Giampaolo Pozzo says the proposal was rejected because he regards Sanchez as a special player almost without equal, and does not want to lose him for at least another 12 months.
"As far as I am concerned, Sanchez is worth as much as Leo Messi, but admittedly I'm not objective," said Pozzo.
"He's one of only two or three players born in every generation.
"We have received an offer of €35m that we rejected. I do not want to name the club, out of respect.
"Sanchez is very young and we'd like him to stay for another year, plus we believe he's worth more than €35m."
Another player linked with a move away from Udinese is midfielder Gokhan Inler, who has been targeted by Napoli.
Pozzo admits there could be developments later in the week, but first wants to enjoy Udinese's achievement of qualifying for the UEFA Champions League.
He said: "Napoli have been pressuring us for Inler for some time now, but we want at least 48 hours to celebrate before talking about such matters."