has been backed for a new role at after suffered a season-ending injury in Sunday's defeat to Crystal Palace. The 27-year-old tore his cruciate ligaments to turn a torrid afternoon at Old Trafford into a disastrous one for Ruben Amorim, who must now replace his first-choice centre-back.

Martinez has been a stalwart on the left of Amorim's back three since he replaced Erik ten Hag as United boss in November.

And the Argentine was recently rediscovering his best form after previous injury lay-offs resulted in inconsistent performances and a battle to restore his physicality.

However, the cruel blow could rule him out for the remainder of the calendar year, leaving Amorim scrambling to fill the void until the summer.

Ayden Heaven - a January arrival from Arsenal - is now United's only fit left-footed centre-back. But the 18-year-old has only played 10 minutes of senior football and will need to be bedded in carefully.

Harry Maguire has experience playing as the left-sided centre-half, but his lack of pace is a concern. The same applies to Jonny Evans and Victor Lindelof.

Meanwhile, Matthijs de Ligt is more suited to the central and right positions, and Leny Yoro is still adapting to English football.

Noussair Mazraoui has featured at right-centre-back under Amorim and could be a hot candidate to replace Martinez, given his versatility.

However, Ally McCoist believes Dalot is at the front of the queue, with Luke Shaw's injury woes refusing to go away.

"I think Diogo Dalot's the obvious one. I mean, I don't know what's going on with Luke Shaw. That's another one," McCoist told Express Sport with talkSPORT BET.

"If he's going to continue to play that three at the back, the obvious one would be Dalot. I know Shaw's played centre-back before, if they can get him fit. I don't know how far away he is.

"But it's a little bit of a shame because of the way he plays that back three. I think Dalot wide in the back four has been one of the plus positions and one of the plus marks.

"He's done alright in that position. It suits him getting up and down, and you would obviously take that away from him if he moves to centre-back, but I think that's the obvious choice."

Dalot has primarily played left-wing-back since Amorim took charge, but Patrick Dorgu's £29million arrival from Lecce in January covers that position.

The Portugal international will likely switch to right-wing-back in the coming weeks but could drop further back to cover for the loss of Martinez.