Manchester United manager Erik ten Hag says he's facing playing the rest of the season without a recognised left-back because of injuries to Luke Shaw and Tyrell Malacia and revealed that on-loan Sergio Reguilón was allowed to leave in January because he was assured by medical staff that the pair would be fit for the second half of the campaign.

Malacia, according to Ten Hag, is unlikely to play at all this season while he continues his recovery from a knee injury suffered last summer.

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Shaw, meanwhile, has an outside chance of being ready for "the last games" but is already a doubt for the European Championships in Germany because of a muscle problem.

In their absence, Ten Hag has been forced to use centre-back Victor Lindelöf and midfielder Sofyan Amrabat at left-back, something which is now set to continue for the remaining months of the campaign.

"We talk about one of my biggest frustrations," said Ten Hag, when asked about Shaw and Malacia.

"You can accept in a position that a player is not available, but when two players are not available over the course of the season, that is very frustrating, because that is also very difficult to catch up as a team but we dealt with it in the best way, but of course it is a disadvantage."

United signed Tottenham left-back Sergio Reguilon as emergency cover last summer and the Spaniard made 12 appearances in all competitions for Ten Hag's side. But his loan spell was cut short in January and the 27-year-old is now on loan at Brentford.

"In December, I had the talks internally, with the medical and performance [staff]," said Ten Hag, when asked why Reguilon was allowed to leave.

"They assured me they [Shaw and Malacia] will both be fit in January and so you will have two left full-backs. Then you have a third one, so I would always have to disappoint one full-back." Malacia hasn't played for United since May and last played a competitive game in the Netherlands' 4-2 defeat to Croatia in June.

Shaw hasn't featured since United's 2-1 win over Luton Town in February and has been restricted to just 15 appearances in all competitions this season.

"I think it's going to be difficult for him [Malacia] this season to be available," said Ten Hag.

"He will fight, he's back on the pitch, but not in the team and the process had some setbacks for him and he's still going forwards really slowly, and the season is coming to an end.

"I think it's the same [for Shaw], maybe for the last games of the season, but we don't expect him back this or next month."