Besiktas attacker Jose Sosa is pushing to join AC Milan.
Sky Sport Italia says the striker has walked away from the pre-season retreat and is facing a huge fine from Besiktas.
Besiktas are also warning they are prepared to take the matter to FIFA arbitration in order to get 'their' player back.
The 31-year-old is determined to push through a move to Milan after spells at Estudiantes, Bayern Munich, Napoli, Atletico Madrid and Metalist.