The Belgium international has been linked with a return to Chelsea following another prolific season in the Premier League, where he finished second in the top goal scorer's list with 25 goals, four behind Harry Kane.
"Lukaku had a promise that if certain clubs came this summer that he could leave this summer," his agent, Mino Raiola, was quoted as saying by talkSPORT.
"We are not in concrete talks with anybody at this moment, but hearing the market I think some clubs will contact Everton for him.
"Yeah, if the price is right for Everton and the project is right for Lukaku then I think he will want to make another step - but we are not there yet."
Raiola had previously said there was a 99.9 percent chance of Lukaku signing a new deal with the Toffees.
He added: "You know we have the 0.1% now. At that moment we decided not to sign the contract.
"But I have to say the relationship with the club is very good and we knew if this summer someone would come and satisfy Everton then there is a possibility that he leaves, yes."