I've noticed a few are suggesting Cakir may be backup for the final. My question in response would be, is a referee allowed to officiate the final twice? As he has already reffed the 2015 final....
Looking at historical appointments, at first glance I can't spot anyone refereeing the final twice? I'm sure someone will prove me wrong though!
Concetto Lo Bello refereed the European Cup Final twice, in 1968 and 1970, but I don't think anyone has refereed that Final or the CL Final twice since then.