By North-west correspondent Alex Stevens

Louis van Gaal has confirmed that Wayne Rooney is set for a spell on the sidelines as he joins the growing Manchester United casualty list.

As reported by Football Insider earlier on Wednesday, the Manchester United captain is facing up to two months out with knee ligament damage.

The England and United skipper did not travel to Denmark with the rest of Louis van Gaal’s squad for the team’s Europa League clash against FC Midtjylland on Thursday night.

It was initially thought that Rooney had been given a rest ahead of a gruelling run of fixtures, which includes three matches in just six days next week.

But Van Gaal revealed that the striker is now one of a staggering 13 players unavailable for selection.

“We have 13 players injured and Wayne is one of them,” the manager said at his media briefing on Wednesday evening, although he stopped short of giving a timeframe on how long Rooney will be out. “You can never say. He has a knee problem so we have to wait and see.

Van Gaal hinted that Rooney suffered the injury in the closing stages of United’s 2-1 defeat at Sunderland last Saturday but played on through the pain barrier.

“That’s also typical Wayne. He’s a guy who wants to go until the end and if he is feeling pain, he doesn’t want to go away, and certainly when you are drawing a match because he wants to win.

“That’s a fantastic attitude but also it’s bad for his body. You do not know when it happened, so that’s the difficulty.”

Louis van Gaal's position at Manchester United is under growing threat

Dark days: Van Gaal is set for a lengthy spell without skipper Rooney

Rooney could miss up to 16 matches with an injury that could rule him out until mid-April.

Rooney has made 32 appearances for United this season, a record bettered only by Chris Smalling (37), Daley Blind and Juan Mata (both 36).

The 30-year-old’s form has been mixed during what has been a troubled campaign at Old Trafford, but he has been back to somewhere near his best since he was dropped for the 2-0 Boxing Day defeat at Stoke. Rooney has scored seven goals in his last nine United appearances.