Manchester United will be serious underdogs when they welcome Liverpool to Old Trafford on the weekend.

Liverpool are currently sitting pretty on the top of the Premier League having won all eight of their games.

United, on the other hand, are struggling massively.

They've picked up just nine points from their opening eight games and are only two points clear of the relegation zone.

Sunday's match is undoubtedly their most important game of the year so far but they could well be without one of their most influential players.

David de Gea was in fine form for his country against Sweden on Tuesday night.

However, he appeared to have a problem with his groin midway through the second half.

De Gea pulled up immediately after clearing the ball.

He was eventually forced to come off, with Kepa Arrizabalaga coming on to replace him.

Watch De Gea come off injured below:

That could well be a huge blow. It's unknown how serious the injury is at the moment, but it must be a real worry for Ole Gunnar Solskjaer ahead of his side's most important game of the year.

Sergio Romero is perhaps the best second-choice goalkeeper in the Premier League and will get his chance if De Gea does not recover in time.

But United fans will be praying De Gea is able to start against their fierce rivals.

United have a number of injury doubts for Sunday's game.

There are also question marks over the fitness of Paul Pogba, Luke Shaw, Aaron Wan-Bissaka and Anthony Martial.

In contrast, Liverpool are expected to be near full strength. 

They have been without Alisson Becker for the past few months after he suffered an injury against Norwich in August. 

But he returned to training on Tuesday and is expected to play on Sunday.