While Koeman is hoping the 23-year-old Belgium international will stay, he wants to build an attacking line that can share the goalscoring responsibilities next season.
"I don't know (if Lukaku will stay). We will see what will happen at the end of the season," Koeman told a news conference ahead of Sunday's home clash with league leaders Chelsea.
"First of all we like to keep the best players but that is difficult. I think we need (more options) offensive wise.
"The scoring gap between Lukaku and rest of the squad is too big. We need more players aged 26, 27, 28."
Everton, lying seventh, have maintained an impressive home record this season, losing just once in 17 games.
Having made Goodison Park a fortress in his first season at the club, Koeman believes opponents are now wary of the threat his side can pose.
"You want your home form to be good, to be intimidating and for the whole experience for opposition teams to be intimidating," Koeman added.
"We have good momentum at home right now... Opposition teams have more doubts these days when they come to Goodison, and that's a good thing."
Chelsea thrashed Everton 5-0 in the reverse fixture at Stamford Bridge in November.
(Reporting by Hardik Vyas in Bengaluru; editing by John Stonestreet)
Share
