Luke Shaw and Sofyan Amrabat are both out of Manchester United's Boxing Day match at home to Aston Villa.
It is understood the duo are sidelined with minor issues and it is unclear if they will regain fitness in time for United's final fixture this calendar year at Nottingham Forest on Saturday.
United have now recorded 34 separate cases of injury or illness that has led to a player missing a game.
Shaw was sidelined for three months earlier this season with a hamstring tear but this is the first medical issue Amrabat has sustained as a United player.
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Amrabat joined United on loan from Fiorentina with an injury that caused him to miss the defeats to Brighton and Bayern Munich in September.
Diogo Dalot, back from suspension, replaces Shaw and switches to left-back. Amrabat did not start in the 2-0 reverse at West Ham on Saturday.
United are already without Tyrell Malacia (knee), Harry Maguire (groin), Victor Lindelof (groin), Lisandro Martinez (foot), Casemiro (hamstring) and Mason Mount (calf). Anthony Martial is still missing due to illness.