On 17 January 2012, Sørensen was officially sent to Bologna in a co-ownership deal for €2.5 million (initially in a cash-plus-player deal, for Saphir Taïder). Despite making just three league appearances for his new club during the remainder of the 2011–12 Serie A campaign, the young defender became an integral part of his club's first team throughout the 2012–13 Serie A season, after they had renewed the co-ownership agreement with Juventus.