Manchester United could be without the services of Noussair Mazraoui for Saturday's clash with Brentford.
Mazraoui was not pictured training with the Red Devils on Thursday, leading to suggestions that the Morocco international has suffered a fitness problem which could rule him out of this weekend's Premier League clash.
Sam Mather was instead drafted into the first-team training group, with the Englishman being used as a right-sided wing-back in the drills, being a natural replacement for Mazraoui when it came to the exercises.
There has been no official confirmation from Man United regarding a potential injury, but his apparent absence from Thursday's session does suggest that he is carrying a knock.
Red Devils head coach Ruben Amorim will be asked about the situation when he speaks to the media on Friday to preview the contest with the Bees at the Brentford Community Stadium.
Mazraoui 'missing' from Man United training on Thursday
Mazraoui missed Man United's first three matches of the season with a muscular problem that he picked up in the team's opening pre-season friendly against Leeds United.
However, the 27-year-old featured off the bench against Burnley on August 30 before being named in the starting side against Manchester City and Chelsea in England's top flight.
The defender has been a vital player for Man United since arriving from Bayern Munich in August 2024, making 60 appearances for the Red Devils, providing three assists in the process.
Man United recovered Diogo Dalot earlier this week, with the Portugal international back in training following a muscular issue, but Lisandro Martinez is still recovering from a long-term knee injury.
Amorim facing big decisions for Brentford clash
Man United head coach Amorim is facing a number of big decisions when it comes to his team selection for Saturday's clash against Brentford, as Mason Mount and Matheus Cunha both returned from injury against Chelsea.
Casemiro is suspended for this weekend's match following his red card last time out, so Manuel Ugarte or Kobbie Mainoo could be introduced in the middle.
However, bringing Cunha and Mount back into the side would almost certainly lead to Benjamin Sesko dropping down to the bench, with Bryan Mbeumo an absolute certainty to face his former club.
Dalot could feature as the right-sided wing-back if Mazraoui is ruled out, as Amad Diallo has struggled in that area of the field during the 2025-26 campaign.