Toffees boss Koeman believes the Belgium international is a better all-round player this season, irrespective of the 24 goals which have made him the Premier League’s top scorer.
Lukaku, who has told the club he will not sign a new contract to replace the existing two years on his current deal, is already six better than last year’s top-flight total and while that has helped Everton secure Europa League football, it has made him even more of a target for potential suitors.
“He has scored 24 goals and with five games to go he can reach a really high total,” said Koeman, who refused to speculate on suggestions the club have put a £100million price tag on the 23-year-old.
“It is like for any player who is performing at a high level – every team likes to have goalscorers in the team because goals make points for the team.
“But I think he is improving in the rest of his football. He is doing better pressing and running in the channels. He is now a better striker for the team than he was last year.
“I’ve had several conversations about how, in my opinion, he needs to play as a striker and he is working hard and improving.
“If someone is interested for sure they will call the board and then we will speak about it but we will try to do everything to keep him at Everton next season.”
Hibs' boss Neil Lennon has leaped to Graeme Murty's defence saying it is the Rangers players who at fault for their latest failing.
League One player of the year Bradley Dack scored twice as Blackburn came from behind to defeat Peterborough 3-1 at Ewood Park.
Brentford will continue to assess midfielder Alan Judge ahead of Saturday's Sky Bet Championship match against QPR.
Sunderland boss Chris Coleman hopes to have Adam Matthews, John O'Shea and Billy Jones available for Saturday's clash with fellow relegation battlers Burton.
Leeds trio Pontus Jansson, Liam Cooper and Adam Forshaw could return to contention for the visit of boss Paul Heckingbottom's former club Barnsley.
Bristol City forward Jamie Paterson is expected to return to contention for the home game against Hull.
Ipswich will have midfielder Bersant Celina available again following illness for the Sky Bet Championship match against promotion-chasing Aston Villa.