The 27-year-old, a three-time Italy international, will join Atalanta on a season-long loan with an option to buy him for €3m.
Piccini is due in Bergamo this evening for his medical tests before signing with Atalanta.
He wore the shirts of Fiorentina, Real Betis and Sporting CP before joining Valencia for around €10m in 2017.
Just two games into the 2019-20 La Liga season, Piccini suffered a fractured kneecap and has not played since.
Piccini is now ready to go again and will continue his career back in Italy with Atalanta.
But disagreements with the player’s agent led to the proposed move falling through.