SportItalia claims that Milan's owners, Elliott Management, stepped in and blocked the deal. The report states that the agent of Denis Suarez requested a high commission, which the American hedge fund wasn't too keen on allowing. Therefore, despite all the details being in place, the transfer was blocked. 

 

This allowed other clubs to re-enter the race for the Spanish winger. Arsenal took full advantage of the collapsed move to Milan, signing the player in the last days of the transfer market. The Gunners brought Suarez in on a paid loan for the remainder of the season.