Arsenal are reluctant to lose David Ospina to Besiktas.
Ospina, 27, joined Arsenal on their pre-season tour of America having been allowed extra time to recuperate after Colombia's Copa America exploits, says the Daily Star.
The stopper has been linked with a high-profile switch to Besiktas, who have contacted Arsenal about his availability.
Besiktas club president Fikret Orman said: "Arsenal want a lot for him, so we may have to look for alternatives.
"I do want Ospina and we are going to get a foreign keeper."