Besiktas chairman Hasan Arat says Joe Worrall has rival transfer interest in Turkey.
Worrall is on-loan at Besiktas from Nottingham Forest to the end of the season.
Arat said: "We hired Joe Worrall as a centre-back. 500,000 euros is on loan.
“A big club in Turkey sent a guarantee of 4.5 million euros to his club, but Joe Worrall wanted to come to us."
For the moment, no decision has been made about a permanent deal.