With Castagne set to leave the club to join Leicester, Atalanta are on the verge of completing a deal for the Belgian's replacement: Rick Karsdorp from Roma.
The 25-year-old Dutchman, who spent last season on loan to Feyenoord, will sign a contract extension with the Giallorossi (due to financial reasons) and then join Atalanta on loan with an obligation to buy set at €7 million.