Romelu Lukaku's agent Mino Raiola claims a new contract is "99.9 percent" done, but offered no guarantees the striker would stay at Everton in the long term.
Press Association Sport reports that Lukaku, whose current Toffees deal runs until 2019, is set to become the club's first £100,000-plus-a-week player when he signs the new terms.
Everton fended off interest for the Belgium international in the summer, with Chelsea and Juventus reportedly interested, but Raiola said a new contract would not necessarily prevent his client from leaving at the end of the season.
"With Everton, we have 99.9 percent reached terms," he told talkSPORT. "We are talking to the club in a good spirit so we are very hopeful. There are no problems on the way that I foresee. I don't see any big problems. It is a question of putting the details on the paper."
Lukaku joined the Toffees from Chelsea for a club-record £28 million in 2014 and has scored 70 goals in 142 appearances. Last season he became the first Everton player since Gary Lineker to score 25 league goals in a single campaign.
Such form attracted interest from a number of clubs but Everton were able to resist advances and persuade Lukaku to stay to work under new manager Ronald Koeman in the summer.
However, there is likely to be a repeat at the end of this season and Raiola gave no assurances the outcome would be the same.
"If Romelu is good enough, strong enough, to move in the next year then we will talk to Everton about it," he added. "It is a very good relationship at the moment. We know what both parties want.
"Everton is going through a transition from a club that was maybe aiming for Europa League and now they are more ambitious and maybe in the near future will go into the Champions League or maybe even win the Premier League at a certain stage.
"In football, you can't look too much in front. You need to take it one transfer window at a time. For now, we are agreeing terms and then we will see in the summer what happens and how the situation is.
"If there is an interest from both parties to move on, then we will talk with the club, but at this point we only have one objective and that is to perform as well as possible for Everton."