The Goodison Park boss was quoted by Belgian newspaper HLN during the international break as saying Lukaku would have “left something behind” in terms of reaching his potential if he was to remain with Everton for the rest of his career.
But Koeman believes the 23-year-old’s abilities can encourage and inspire the Merseyside outfit to greater heights.
“It is not to defend myself but you take the headline out of context,” he said at a news conference ahead of this weekend’s clash with Swansea City. “Of course what we like to show Romelu is that Everton will grow, we will be bigger and we will fight for titles.
“If you look now at Everton, and if Everton stays at this level, then of course it is not good that he finishes his career at Everton because he is one of the best strikers and he is still only 23. If he stays for more years that is not bad for his career, he is improving and learning and he is one of the better strikers that we have in the Premier League and in Europe.
“Of course there is a lot of interest in the player and finally the player needs to make a decision and a club needs to make a decision to accept – yes or no – but what I tried to do is keep Romelu for as long as possible at the club.”
Lukaku was a reported target for Bayern Munich and former club Chelsea earlier this year and Koeman concedes Everton could have a fight on its hands to keep a man with seven goals in 10 Premier League games this season when the current campaign ends.
“The problem in the summer is the problem for the summer and, of course, we need to prepare for Romelu’s position and other positions,” he said. “That is our job and what we need to do. He took the decision to stay because he had a good feeling with what was happening from the start of this season.
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“If we show the team, the management, the club and the board are growing and we invest and we are improving and playing for Europe that is the first step for the ambition of players.”
Of more immediate concern to Koeman is his team trying to bounce back against struggling Swansea after an impressive start to the season was derailed by a 5-0 loss at Chelsea.
“That was unacceptable,” he added. “You can lose but not in the manner we lost. We made it too easy for them. I am very optimistic we will get a good reaction.”