Roberto Martinez has dismissed suggestions Everton are thinking about selling Romelu Lukaku following claims from his agent Mino Raiola.
Lukaku has been a key figure for Everton ever since joining from Chelsea in 2013, with the deal becoming permanent in 2014 after an initial season-long loan.
The Belgium striker has netted 30 goals in 77 Premier League games for the Merseyside club, and his performances have led to speculation that he could leave Goodison Park if the price is right.
But, speaking ahead of this weekend's clash with Sunderland on Friday, Everton boss Martinez said: "Lukaku has been a real joy to see developing.
"He has had a very important role with us from a young age. He is now in a position to take on more responsibility on the pitch.
"We want him to keep enjoying his football and play an important role for us. Agents have the right to say what they want. That is their prerogative. But Romelu has an important role with us."
Lukaku will be looking to add to his tally of five Premier League goals this season in Sunday's encounter with Sunderland, but Martinez warned that Sam Allardyce's men - who beat rivals Newcastle United last weekend - will be no pushovers.
The Spaniard added: "Allardyce is already making an impact at Sunderland. There is a new method of working and playing. There is plenty of quality in his squad.
"They are always going to need a bit of time, but they have been impressive in the past two games. They will only get better the longer they work together. It will be a tough match.
"It's been a really demanding start of the season, but we are looking forward to the next few games. We will see over the next nine games where we stand compared to the rest. There are no easy games in this competition. We are keen to face all opponents and see where we are."
Everton will possibly without Seamus Coleman on Sunday, while Muhamed Besic and Leighton Baines are confirmed absences.
Martinez continued: "Coleman is a huge questionmark. He has had a stomach bug and has lost a fair bit of weight.
"Besic and Baines are resuming squad training on Friday, but are not ready for the weekend."
