Napoli has had its fears confirmed with the news that Kevin De Bruyne has a severe lesion to his thigh muscle and will be sidelined for several months.

De Bruyne immediately pulled up and clutched the back of his right thigh after converting a penalty to set Napoli on the way to a 3-1 win over Inter Milan on Saturday.

The former Manchester City midfielder looked distraught and had to be helped off the field by two medical staff. He was later seen sitting on the bench with his thigh heavily strapped and crutches alongside him.

"Following the injury that occurred during the match against Inter, Kevin De Bruyne underwent instrumental tests at the Pineta Grande Hospital and that showed a high-grade lesion to the femoral bicep in his right thigh," Napoli said in a statement on Monday.

"The player has already started the rehabilitation process."

The Serie A team did not give an indication of when De Bruyne is expected back but it is a similar injury to that sustained by Napoli and Belgium teammate Romelu Lukaku during a preseason friendly. Lukaku will likely be back in January.

The penalty took De Bruyne`s tally to four goals in eight Serie A matches. It also helped send Napoli joint top of the league but it could have come at a hefty cost.

Fellow midfielder Stanislav Lobotka is also out injured while Frank Anguissa will be with Cameroon at the Africa Cup of Nations between December and January.

The news will also be a blow to Belgium which has crucial World Cup qualifiers coming up next month. De Bruyne has netted six goals in his past five matches for his country.