Inter suffer injury blow with star midfielder ruled out for over a month ahead of derby showdown against AC Milan

According to La Gazzetta dello Sport, the Armenian international's injury, sustained during the 3-1 defeat to Napoli, is serious enough to keep him out of at least seven crucial upcoming fixtures for both domestic and European competition.

Inter released an official statement on Monday confirming the nature of the 36-year-old's injury after he underwent medical evaluations.

"Henrikh Mkhitaryan underwent clinical and instrumental tests this morning at the Humanitas Institute in Rozzano," the club statement read. "The tests revealed a strain in the semitendinosus of his left thigh. His condition will be evaluated next week."

The problem will keep the midfielder out for at least a month, with a potential return not expected until early December.

The timing of the injury is a major setback for Nerazzurri coach Chivu. Mkhitaryan is now set to miss a total of seven games during a packed schedule.

His absence will be most keenly felt in the five upcoming Serie A matches: fixtures against Fiorentina, Verona, Lazio, Pisa and the high-stakes derby against city rivals AC Milan.

The Armenian, who has started 75 per cent of Inter's league games this season, will also be unavailable for two vital Champions League clashes against Kairat Almaty and Atletico Madrid, as the Nerazzurri fight to secure their standing in the group stage.

While Inter have alternatives in midfield, including Piotr Zielinski who replaced Mkhitaryan at the Stadio Diego Armando Maradona, the loss of the veteran's experience is a significant one. Chivu must now navigate a difficult period without a key component of his squad.

The earliest expected return date for Mkhitaryan, who has hinted that this could be his last season before he retires from the game altogether, is the Coppa Italia match against Venezia on December 3, or the following Serie A fixture against Como three days later.

The injury compounds a difficult weekend for Inter, who sit fourth in the Serie A table following their loss to league leaders Napoli. The controversial clash saw Antonio Conte and Inter star Lautaro Martinez involved in a spat on the sidelines during the intense Serie A clash, in which Kevin De Bruyne sustained an injury after converting the penalty that gave Napoli the lead. After the match, it was reported that the referee Maurizio Mariani and his assistant, Daniele Bindoni, being demoted from the Italian top-flight for the time being.

Chivu's side must now prepare for a tough run of fixtures without Mkhitaryan, starting with their upcoming league match against Fiorentina, as they aim to keep pace with AC Milan, Roma and Napoli at the top of the table.