The Belgium international has sprained knee ligaments and will be sidelined until the beginning of November.

It means he will miss Saturday’s crunch clash against Liverpool at Anfield.

Fellaini suffered the injury during Belgium’s 4-3 win over Bosnia and Herzegovina at the weekend.

At first it was feared the 29-year-old had ruptured his knee ligaments and would miss the rest of the season.

But he has avoided a long-term lay-off after scans revealed the problem was not as bad as first feared.

Starsport understands Fellaini has sprained his Medial Collateral Ligament (MCL) - which will keep him out for at least three weeks.

The news is still a big setback to United boss Jose Mourinho, with the Belgian having made a strong start to the season to emerge as one of Manchester United’s most influential players.

His absence will limit Mourinho’s midfield options even further with Paul Pogba out for some time with a hamstring problem and Michael Carrick also struggling, which means Ander Herrera will almost certainly start on Saturday.

Fellaini will also miss United’s games against Huddersfield, Spurs and both Champions League games with Benfica.