The 21-year-old, who spent time on loan at Vitesse last year, failed to make the grade at Camp Nou after 15 years with the Catalan giants and will now continue his career in Italy
The Rossoblu announced on their official website that the 21-year-old Blaugrana youth team product will be formally presented to the media at a press conference at 12:00CET on Thursday.
However, the Italian outfit did not disclose any details of the deal.
Riverola has been with Barca since he was six years old but he made only one senior appearance for the Catalans, as a substitute in the Champions League victory over BATE Borisov at Camp Nou last December.
He made a total of 36 appearances for the Blaugrana's B team, and also played 15 times for Vitesse during a six-month loan spell with the Eredivisie side last year.