Ghana midfielder Bernard Mensah was replaced at half time in Besiktas' comeback win against Goztepe on Sunday.
The 26-year-old was replaced by Adem Ljajic in the 46th minute after appearing to have picked a knock.
It is yet to be determined the extent of his injury but the former Atletico Madrid player will under some medical examinations in the coming days.
Meanwhile, his replacement Ljajic wasted no time in announcing his presence after equalizing for Besiktas who were down to a Zlatko Tripic opener for Goztepe in the first half.
Cameroonian forward Vincent Aboubakar grabbed the winner for the Eagles with 13 minutes left.
Mensah is currently on loan from Kayserispor and has made 18 appearances for Besiktas in the Super Lig, scoring four and providing an assist.
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