The Turkish international completed a move to Barcelona yesterday evening for £24 million that the Catalan giants confirmed on their official website.
However, Barcelona are currently preparing for new presidential elections on 18 July. Bartomeu, Joan Laporta, Toni Freixa, Agusti Benedito and Joan Batiste are the candidates hoping to take charge at the club.
The winning president could veto the Turan deal and send the bearded winger back to Atleti.
This would mean both United and Chelsea – who were closely linked with the Turkish international – still have a slim hope of signing Turan should Atleti buy the winger back and sell him off again.
Turan will be unable to play an official game for Barcelona until January 2016 due to a transfer ban imposed by FIFA for breaching rules over the signings of underage players.
The 28-year-old winger provided six assists and three goals in 46 appearances in all competitions for Atletico Madrid last season.