 On 15 October 2014, the club announced that the buying option has been used, making Sosa's move to the Turkish side definitive, for €3.4 million.In the 2015–16 season, Sosa served 12 assists in 2015–16 Süper Lig, at least 4 more than any other player.On 17 August 2016, Sosa joined Italian club A.C. Milan for €7.5 million fee, signing a two-year deal.