Manchester United star Kobbie Mainoo is reportedly set to spend several weeks on the sideline with a muscle injury. In the latest blow to manager Erik ten Hag, the Dutchman will be missing another of his key players for a crunch Premier League clash with Brentford.

United noted in their weekly team news article that Ten Hag will be hoping that the injury which forced Mainoo out of England duty last week has "subsided". The 19-year-old has started all seven of the Red Devils' Premier League matches this season, enjoying a prominent role under his manager.

However, the Daily Mail reports that Mainoo is set to miss 'weeks' of action due to his muscle problem. The Three Lions star was forced off just before half-time during the 3-0 defeat by Tottenham at the start of October and subsequently missed the 3-3 draw with Porto three days later.

Mainoo returned for the goalless draw with Aston Villa, playing 85 minutes during United's final outing before the international break. However, he then pulled out of England duty ahead of his country's Nations League matches against Greece and Finland.

That prompted fresh fears over his fitness and it seems United are set to miss the academy graduate for a number of games. It is the latest setback in a lengthy list for Ten Hag, who is fighting for his future.

The Dutchman will be without Harry Maguire, Mason Mount, Luke Shaw, Tyrell Malacia and Leny Yoro for the visit of Brentford. Noussair Mazraoui underwent an operation to address heart palpitations prior to the international break and it remains to be seen whether the right-back will be available.

Alejandro Garnacho and Amad Diallo joined Mainoo in withdrawing from their respective national teams. Garnacho had a knee injury while Amad was reported as being ill, returning to Manchester from the Ivory Coast.

Meanwhile, Manuel Ugarte limped off with a knee injury late in Uruguay's goalless draw with Ecuador on Tuesday night. No update has been provided on the summer signing.

Despite winning just two of his first seven Premier League matches this season, Ten Hag is set to be given the opportunity to improve results. However, it is unlikely that he will get his best team on the pitch for at least several weeks. The 3-0 drubbing by Spurs and underwhelming performances against Porto and Villa have placed his job at risk.