France midfielder Paul Pogba is a major doubt for the World Cup in Qatar as he requires surgery on a knee injury. The 29-year-old, who left Manchester United for Juventus in the summer, has yet to feature this campaign after sustaining the injury in pre-season and the club have decided he needs surgery to fix the problem. France's first match of their World Cup defence is against Australia on November 22 and Juve boss Massimiliano Allegri has ruled out Pogba appearing for his side this year. However, that does not mean he will not be fit to play until January as the Italian league season stops for the World Cup in mid-November and does not resume until 2023. "Last month Pogba decided not to have surgery after damaging his meniscus in training following his close season switch, but Allegri said circumstances had changed after he tried to train again. This morning Pogba trained for the second time, but then stopped, and it was then decided that he undergo surgery," Allegri said on Monday during a press conference ahead of their Champions League opener against Paris St Germain. "We will realistically get him back in January. "The World Cup is not my problem, Juventus' problem is that he comes back in January." Pogba was instrumental in France's World Cup victory in 2018 in Russia, scoring in the final where they beat Croatia 4-2 to lift the trophy after a gap of 20 years. He has scored 11 goals in 91 appearances for France. His injury comes at a difficult time as he has accused his brother Mathias of extortion. French authorities are investigating allegations Pogba was the target of an extortion plot by his brother and childhood friends who demanded EUR13 million. Paul Pogba reportedly told investigators the blackmailers aimed to discredit him by claiming he asked a witch doctor to cast a spell on French superstar Mbappe. Pogba denied that allegation and Mbappe sided on Monday with his international teammate. "He called me, he gave his version of the facts," Mbappe said. "It's his word against the word of his brother. I prefer to believe the word of a teammate. "He (Paul Pogba) already has certain problems and I think it's not the time to add to them for him. We'll see how that all goes, I'm pretty detached from all that." French officials have said Pogba paid EUR100,000 to the group, reportedly after he was threatened by masked, armed men in a Paris apartment in March. With agencies Australian Associated Press