During the summer, Everton failed to replace top goalscorer Romelu Lukaku, and it had been reported that Ronald Koeman was keen on bringing Onyekuru back to Goodison Park during the January transfer window.
However, it has been revealed that the Nigerian international must remain at the Belgian club for the rest of the season.
An agent told OwnGoalNigeria.com: "It's unfortunate that he can't join Everton till the summer, as there is no break clause in his loan deal and aside that he is not qualify for a work permit yet.
"The plan for now is still the same like in the summer, which is spend a season on loan before returning back to Everton next summer to fight for a shirt in the team."
The 20-year-old has scored six times in 12 appearances for Anderlecht, with three of the player's outings coming in the Champions League.