Rio Ferdinand has criticised Erik ten Hag for his treatment of Manchester United midfielder Casemiro and urged him not to play him as a defender again.

Casemiro started at centre back alongside Jonny Evans for the 1-0 defeat by Arsenal at Old Trafford but made a horror error in the build-up to the only goal of the game.

The veteran midfielder played Kai Havertz onside after failing to push up the pitch, allowing the forward to cross for Leandro Trossard to sweep home at the near post.

United, who are missing the likes of Lisandro Martinez, Harry Maguire, Raphael Varane and Victor Lindelof at centre half, also fielded Casemiro in the backline in the 4-0 loss at Crystal Palace, where he made two more mistakes leading to goals.

With the 32-year-old visibly struggling in his emergency role, United legend Ferdinand has insisted he would rather other players stepped in instead for the rest of the season and blamed Ten Hag for being 'unfair' with his decision-making.

'When is he going to take Casemiro out of the back line?' Ferdinand said on his YouTube channel, Rio Ferdinand Presents Five. 

'Why can't Sofyan Amrabat play there? Or Scott McTominay? I just don't think it's fair.

'If you see a few mistakes from someone who is playing there, who has never played there before, and you see the mistakes early, you should go, "You know what, I'm not going to do this to you" – I don't care how experienced he is.

'Come on, move him out of there and get back to the position he knows. Play Aaron Wan-Bissaka there. Then you could have Amrabat at right-back. 

'That's the most natural thing for me. Wan-Bissaka at centre-back and Amrabat at right-back. He was happy to play him at left-back for a few games.

'We looked like an uncoached team. At the creative end of the pitch, we were lacking massively. Decision-making and quality was not there.'

Fellow United greats Wayne Rooney and Roy Keane ripped into Casemiro after his nightmare performance and branded him 'lazy' for his role in Arsenal's goal.  

'It's lazy. He's lazy,' Rooney said in a scathing assessment. 'The rest of his teammates have pushed out and they get caught. He has to get out.

'Whether you're a midfield player or a centre-back, you have to be ready to push out with the rest of the team. If not, you play everyone onside and you get punished.'

Keane added on Sky Sports: 'Casemiro cannot play in the Premier League at centre-half. Whatever shortcomings you have, you can't coach pace. There was a bit of laziness as well in terms of getting out that led to the goal.

'We're not saying Casemiro can cover 60 or 70 yards, it's 10 or 15 yards. You've got to get up the pitch. Just move your feet. Casemiro as a centre-half will get found out, which he did again today. it was the defining moment of the game.'