Midfielder Bernard Mensah missed Besiktas' trip to Hatayaspor on Sunday due to an injury setback.
The 26-year-old missed the Eagles 2-2 draw after picking up a knock in the 6-0 thrashing of Rizespor.
The attacking midfielder complained of pains in his right ankle after the game and had to be omitted from the team that drew against Hatayaspor on Sunday.
Mensah is expected to undergo tests to determine the extent of his injury.
He might miss the games against Rizespor in the Turkish Cup and Sunday's big clash with Galatasaray.
The ex-Atletico Madrid star is currently on loan from Kayserispor and has featured 15 times scoring twice for Besiktas.