By North-west correspondent Alex Stevens

Chris Smalling has been ruled out of Manchester United’s Europa League clash against Midtjylland on Thursday night, Football Insider sources understand.

The defender will miss the second leg of the last-32 tie at Old Trafford with a shoulder injury and also faces  a battle to be fit for United’s Premier League showdown against Arsenal on Sunday.

It is the latest in a seemingly neverending series of injury blows for Louis van Gaal, who was already without 13 players for Thursday’s match, including Wayne Rooney and David de Gea.

Smalling has been a key player for United this season and has established a solid partnership in central defence with Daley Blind.

A United source has told Football Insider that Paddy McNair is expected to come into the team in place of Smalling, who injured his shoulder when he crashed into the hoardings at Shrewsbury during the 3-0 victory over League One strugglers on Monday night.

Smalling has only missed one game this season for United, which proved costly as they were beaten 2-1 away to Bournemouth in December.

In other Manchester United injury news, Marcos Rojo will be on the substitute’s bench against Midtjylland after three months out.