The Belgian club are keen to extend Onyekuru's spell after his promising loan was interrupted by a serious injury. He has made 19 appearances and scored nine goals and recently completed his recovery from the knee problem that sidelined him for months this season.
The Nigerian striker, now 20, was signed by Everton for £8m last summer and immediately loaned to Anderlecht to further his development and to enable him to earn enough international caps to enable him to get a work permit to play in the Premier League.
He is hopeful of making Nigeria's World Cup squad for this summer's tournament in Russia and, should he do so, will feel that he has a better chance of proving himself in the English Premier League with Everton.
He is also said to be stalling until he knows whether Anderlecht will qualify for next season's Champions League.