Roma's sporting director Walter Sabatini says Mehdi Benatia's suitors must pay €61 million to sign the defender.
The 27-year-old Morocco international has been a reported target for Barcelona, Chelsea and Manchester City in recent weeks after an impressive debut season with Roma.
Benatia played 37 times in all competitions as Rudi Garcia's men finished second in Serie A and reached the semi-finals of the Coppa Italia.
And amid interest from high-profile clubs, Sabatini has slapped what would be a world-record price-tag for a defender on the former Udinese man.
"Benatia is a guy with sound principles - he didn't want to take a step away from Roma fans or his team-mates," Sabatini explained.
"He has been completely coherent, he's never played for himself, always with and for the team.
"Personally I think €30m is the value of Benatia's weak foot. If Benatia's weak foot is worth €30m then the total price would be €61m.
"Benatia is not for sale, unless someone comes to us with an offer of €61m."
Roma confirmed on Friday that coach Rudi Garcia had agreed a new deal that will keep him under contract at the Stadio Olimpico until 2018.
With the Frenchman's future secured, Sabtini is keen to ensure they are in the title mix-up again next season while also being able to handle UEFA Champions League football.
Specifically, Verona's Juan Manuel Iturbe is one target the club has in mind, despite the Uruguayan ahving only signed a permanent deal at the Bentegodi last week.
"We'll add to our roster with our European campaign in mind. We need two for each position, and three in some cases," Sabatini added.
"Garcia's task - coaching Roma - is a very difficult one. The club wants to help him with it as best we can.
"I can say this now: Roma will challenge for the title next season. This team deserves it.
"We're looking at Iturbe, as we are lots of talented players. We're always interested in good players.
"We want to be competitive but we'll do it without making financial choices that could have negative consequences on our future."