By North-west correspondent Alex Stevens

Manchester United fear David de Gea could face an extended spell on the sidelines with the knee injury he suffered in the warm-up ahead of their 2-1 defeat at Midtjylland.

De Gea broke down while making his pre-match preparations and pulled out of the team just 15 minutes before kick-off.

He was replaced in the starting X1 by Sergio Romero as United were forced to name a six-man substitute’s bench that did not include a goalkeeper.

The visitors lost their second consecutive match to leave their Europa League hopes hanging by a thread ahead of the second leg at Old Trafford next Thursday.

Louis van Gaal revealed afterwards that De Gea will undergo a scan on his injured knee on Friday as United begin preparations for a run of fixtures that includes three matches next week – against Shrewsbury in the FA Cup on Monday, the second leg of the Midtjylland tie and then the Premier League clash against Arsenal three days later.

Wayne Rooney is facing two months on the sidelines with knee ligament damage

Knockout blow: Rooney is facing two months on the sidelines

“David De Gea has a knee problem so we have to wait and see,” Van Gaal told the media after Thursday’s match. “It happened in the warm up. We have to wait and see for the scan tomorrow, then maybe we can say more but it was a big surprise.”

The Spanish goalkeeper becomes a remarkable 14th United player on the club’s casualty list.

His action comes just 24 hours after captain Rooney was ruled out of action for up to two months with knee ligament damage.