Frosinone striker Federico Dionisi will be out of action for four to six months after rupturing his anterior cruciate ligament.
The 31-year-old forward was decisive in their promotion from Serie B via the play-offs, scoring 10 goals last season.
He picked up a knee injury during the 2-0 Coppa Italia defeat to Sudtirol on August 12.
A statement from Frosinone today confirmed Dionisi has ruptured the anterior cruciate ligament in his left knee.
Surgery will be performed to stabilise the injury over the next few days.