Ander Herrera
Ander Herrera's (C) participation is doubtful for the clash against ChelseaGetty Images/Laurence Griffiths

Manchester United suffer injury blow as reports suggest that midfielder Ander Herrera has aggravated his rib injury suffered earlier in the month.

According to Goal, the Red Devils midfielder, who was substituted during half-time in their game against West Bromwich Albion has aggravated his rib injury and is doubtful for the crucial clash against Chelsea on Sunday.

Herrera was rushed back from his injury, despite earlier reports suggesting that he was going to be sidelined for at least six weeks with a fractured rib.

The report claims that the 25-year-old midfielder was in some discomfort when assessed by United's medical team on Tuesday and is now facing a race against time to be fit for the match against the league leaders.

The Old Trafford club will monitor the player through the week and make a late decision over his participation in the game on Sunday.

United's injury problems are finally easing out with the return of various first-team players like Phil Jones, Michael Carrick and Marouane Fellaini, but the Spaniard's injury setback will come as a big blow to United ahead of crucial fixtures in the coming weeks.

Meanwhile, Ashley Young believes that United can take positives out of the game against West Brom despite only managing a 2-2 draw.

"You have to look at the positives. Obviously they went ahead when we were on top but we came out in the second half and got ourselves back into the game. We take the positives of the possession we had and the attempts at goal," Young told United's official site.

The Red Devils have important matches coming up against league leaders Chelsea and defending champions Manchester City, but the England international insists that United will go into the matches with confidence against the title favourites and come out with some points.

"We've got tough games coming up with Chelsea and [Manchester] City, but we still go into those games with confidence as high as it always is and we'll be looking to get some points from those matches," the United winger added.