Everton will demand full compensation if Besiktas push to end early the loan of Dele Alli.
Besiktas are keen to bring Alli's loan spell to a premature end by sending him back to Everton this month, says Sky Sports.
However, the possibility of a January return to Goodison Park is thought to be highly unlikely at this stage.
There is no early break clause in the deal and Everton will want full payment of the loan fee, which is thought to be around £1m, as well as the agreed wage contribution.
Alli's deal with Everton expires in June.