Everton fielded Matty Foulds in their U18 mini-derby defeat to Liverpool on the weekend.
Foulds, technically, is still a Bury player.
The Liverpool Echo says e Blues will finalise the £225,000 transfer of the Bury teenager when the window opens on January 2.
Foulds, a left-footed defender, has been training with the club ahead of the move but on Saturday morning, started in the mini-derby against Liverpool for Everton's u-18s.
The young Blues lost 2-1 at a windy Kirkby.
Everton can field Foulds as a trialist in two games over the space of a one month period, before signing him.