According to LA SER, the provisional board don't want to exceed their duties
Barcelona's current provisional board has decided that they won't be signing Arda Turan. Not yet. Despite the club's agreement with Atletico Madrid, the board thinks signing a player like Turan would exceed their duties, so they will wait until a new president is elected on 18th July to close the deal.
Now the decision lands on Barcelona's new president, in charge of closing the signing the very first day of being elected. However, there's a risk the player may be in a rush to find a new team and there are various Premier League clubs interested in his signing.
Moreover, Barcelona will begin the pre-season on July 13th, 5 days before the elections. This would mean that Luis Enrique won't have Arda Turan available during the first training sessions. Not so important according that Turan wouldn't be available until January 2016.
Provisional board tasks
Barcelona's provisional board has received a lot of criticism during the last few weeks because some of the candidates consider they have already exceeded their duties. For example selling Gerard Deulofeu to Everton, Montoya on loan to Inter Milano and negotiating with Pogba or Gerson.