Manchester United are back in the midst of another defensive injury crisis amid fears that Marcos Rojo could be out for six weeks with a dislocated shoulder.

Rojo was carried off on a stretcher during United’s Manchester derby defeat to Manchester City at the Etihad Stadium on Sunday and needed oxygen at one point.

Further rests have confirmed the defender’s injury is a full dislocation and the recovery time could be six weeks or even longer. The exact timescale will depend on whether Rojo has torn or merely stretched the ligaments that usually hold the shoulder in place.

VIDEO Scroll down to watch Louis van Gaal call Chris Smalling stupid for getting sent off

Manchester United's Marcos Rojo is facing up to three months out injured after dislocating his shoulder

The 24-year-old was carried off on a stretcher and will be missing for at least six weeks

DID MARCOS ROJO MISTRANSLATE HIS OWN TWEET? The versatile defender seemed to be in some pain when he was carried off against Manchester City after receiving around two minutes' worth of treatment. It was something of a surprise, therefore, to see the 24-year-old play down the injury on Twitter the day after the derby. 'Gracias a todos por los mensajes. Gracias a dios fue solo un mal momento/ thank you all for your messages. thank god it was nothing,' Rojo wrote. United believe Rojo, who speaks only limited English as he has only been in the country for just over two months, made something of a mistake in his translation of the Spanish part of his tweet. 'Solo un mal momento' translates as 'only a bad moment', rather than 'nothing', and the club believe the defender's injury is serious. Rojo was discharged from hospital on Sunday evening and the club confirmed that the defender had suffered a dislocation. Advertisement

Rojo’s father appeared to confuse matters last night when he told a TV station in Argentina: ‘The injury is not too severe. He will miss two or three games.’

However, senior sources at Old Trafford confirmed yesterday that the injury was a dislocation and it seems improbable the £16million signing could recover that quickly.

This means United manager Louis van Gaal will have to plan for the coming weeks of the campaign without the man he bought from Sporting Lisbon in the summer.

With fellow central defenders Phil Jones and Jonny Evans struggling with injuries ahead of Saturday’s Barclays Premier League match with Crystal Palace, and right back Rafael da Silva also on the sidelines, Van Gaal is expected to ask midfielder Michael Carrick to fill in.

Sportsmail revealed last month that Carrick had been told by Van Gaal to prepare for defensive duties on his return from his own long-term injury troubles.

The England international midfielder went straight into the centre of defence when he came on at City on Sunday and is ready to do so again against Palace.

The news comes as a further blow to Louis van Gaal (right), who is struggling with defensive options

Carrick said: ‘That position is not something I have played an awful lot. I have had spells of it, playing two or three or four games in a season.

‘But if I need to play there then fine. I have not had a lot of football recently so I will play anywhere, I don’t mind.

‘Ideally we just need to get players fit and have more options to choose from.’

United began the season with a host of injuries at the back, prompting Van Gaal to hand debuts to Tyler Blackett and Paddy McNair.

Those problems were starting to ease but with Chris Smalling serving a one-game ban after a red card on Sunday, the United boss is back to square one.

Michael Carrick featured for the first time this season for Manchester United against Manchester City

On Monday night Carrick could only hope things will turn United’s way.

‘We look at the points total and we are bitterly disappointed with the amount we have got,’ he said.

‘It is nowhere near good enough for where we want to be. But if you look deeper there are signs we are still going to have a good season.

‘Overall the feeling is we are still building to be successful and I think we will be. Points wise it might suggest we are not close to Chelsea and Manchester City but you look at the Chelsea game, I think we deserved the win.

‘Against City we also felt we deserved more, but that is the way it is going. We are experienced enough to know that points are what you are judged on.

‘It is up to us now to have a big push and put ourselves right back up there again.’

VIDEO Old Trafford defensive crisis for Van Gaal