Besiktas executive chairman Ahmet Nur Cebi is among a spate of positive coronavirus tests in Turkish football.
Shortly after revealing eight unspecified individuals related to the club had contracted Covid-19, Besiktas on Thursday confirmed Cebi had returned a positive result.
The team have reportedly stopped training, with the Super Lig set to return from its suspension during the pandemic on June 12.
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A statement from Besiktas' health team consultant Tekin Kerem Ulku said: "The follow-up and treatment process of the people whose test results were positive has started immediately in line with the relevant procedures.