The Aston Villa captain was one of the stars of the Brazil World Cup helping the Dutch national side finish third in the tournament.
His performances have grabbed the attention of a number of Villa's Premier League rivals, with Southampton the latest to be linked with the powerful centre-back.
He said: "Ron would definitely be an option, although I think he won't be cheap right now. Well, let's just wait and see."
The Birmingham Mail are also reporting that QPR were monitoring the Dutchman's situation at the Midland club.
However having just signed Rio Ferdinand on a free and Steven Caulker for £8 million, it seems unlikely the Premier League new boys will follow-up their interest in Vlaar.
Lambert is determined to keep all his star players at Villa Park for the season ahead, and he hopes Villa chairman Randy Lerner will offer their skipper a new contract once he returns from his extended holiday break.
Said Lambert: “Ron is not only an Aston Villa player, he is our captain, he has one year remaining on his contract — and he is staying here.
“We will be talking with him in due course about extending his deal and we are confident those talks will be positive. Ron has always said that he is really happy here — and has done nothing to suggest anything has changed.
“None of this speculation is coming from him, or anyone connected with him. We aren’t selling. It is as simple as that.”