After scoring 8 goals in 20 games on loan at U.S. Grosseto in Serie B, Sforzini's move was made permanent leaving Udinese Calcio after a 6-year spell at the club. His form in his 2 seasons in Grosseto was impressive, in his first season he scored 21 goals in 40 appearances in all competitions with 20 of those coming in Serie B in the 2011/12 season. He finished 3rd top scorer in Serie B behind Ciro Immobile (28 goals for Pescara) and Marco Sau (21 goals for Juve Stabia).