Napoli forward Lorenzo Insigne faces a lengthy spell on the sidelines after suffering a knee injury in Sunday's 1-0 win over Fiorentina, the Serie A club said.

Napoli said the 23-year-old, who was taken off in the first half of yesterday's game, had suffered a torn anterior cruciate ligament in his right knee.

Napoli, third in Serie A, did not say how long they expected Insigne to be out of action although Italian media said he faced around six months on the sidelines, meaning he was likely to miss the rest of the season.

Insigne, who has six caps for Italy, was starting to find his form after a slow start to the season and had been included in Italy's squad for the Euro 2016 qualifier against Croatia next Sunday.

He earned plaudits from Napoli coach Rafael Benitez for his work rate last month.

"The key for me with Insigne is his work rate," said Benitez. "In football you cannot have a player who stands still, as they need to help out in defence and also attack.

"Lorenzo can do that, he just needs to be a little more precise with his finishing."