The 21-year-old has been the subject of interest from a number of European clubs this summer, with Borussia Monchengladbach and Newcastle United reportedly keen on securing his services.
A delegation of Gladbach officials are already in Netherlands to strike a deal, and hope that the inclusion of young Swedish left-back Oscar Wendt could tip the scales in their favour.
Newcastle are rumoured to have already had a €15 million (£12m) bid turned down by the Dutch club, with a second approach not expected.
However, McClaren has stressed his desire to hold on to De Jong - who netted 25 times for Twente last season - and believes that the forward would be best served staying in Enschede for another season before moving on.
"We do not have to sell and, football being football, everybody has his price," he told Sky Sports News.
"For Luuk de Jong to leave this club then it will have to be a very good offer, one that we cannot refuse, and at the moment no-one has given us that yet.
"There are more than just rumours. There is obvious interest as everyone knows.
"Of course we want to keep Luke de Jong and we want to keep our squad of players as it is. We want to build and not to take players away. We have already sold Ola John and I have told the club I do not want to sell any more.
"I would advise Luke to spend another year establishing himself in Holland doing it again, getting 25 or 30 goals and being a top striker, another year more mature, another year closer to the national team as he is in the squad now."
McLaren's comments come after De Jong's agent revealed that his client was ready to leave the 2010 Eredivisie champions.
"We've made it clear to Twente that De Jong is ready for his next step," Louis Laros told Voetbal International."The important thing considered by him will be how serious the sporting project is. We are not overly concerned about the money, what matters more to De Jong is the club's plans and how they plan to use him.
"I hope that Twente do not lose sight of reality though, and demand only a fair market price."