Northern Ireland defender Jonny Evans will be sidelined for the "next few weeks" due to a thigh strain he suffered in the first half of United's 4-3 Champions League defeat at FC Copenhagen.
Manchester United said late on Friday.
He joins a lengthy injury list at United, who remain without defenders Lisandro Martinez, Luke Shaw, Tyrell Malacia and midfielder Casemiro.
The 35-year-old will miss Northern Ireland's final Euro 2024 qualifiers against Finland and Denmark. Northern Ireland, who sit fifth in Group H with six points, travel to Finland next Friday before hosting Denmark on November 20.
Evans rejoined United on a one-year deal in September, eight years after leaving Old Trafford and has started five league games.
United lie in eighth place in the top-flight after picking up 18 points in 11 matches and host promoted Luton Town later on Saturday.
Novak Djokovic beat young rival Carlos Alcaraz 4-6 6-4 6-3 6-4 in a battle worthy of a title clash to charge into the Australian Open semi-finals on Tuesday and remain in the hunt for a record 25th Grand Slam title.
Antoine Dupont will make a much-awaited return to the Six Nations after a one-year hiatus that cemented his status as one of France's top athletes, hoping Les Bleus can win the tournament on the back of a perfect autumn series.
Alexander Zverev played his best tennis when it mattered most to down Tommy Paul 7-6(1) 7-6(0) 2-6 6-1 on Tuesday and reach his third Australian Open semi-final in five years, keeping alive his dream of finally landing a Grand Slam title.
Defending champion Aryna Sabalenka reached the semi-finals of the Australian Open with a battling 6-2 2-6 6-3 win over Russian 27th seed Anastasia Pavlyuchenkova while Spain's Paula Badosa stunned error-prone third seed Coco Gauff 7-5 6-4.
The Desert Vipers' undefeated streak finally came to an end on Monday, as the Dubai Capitals delivered a stunning six-wicket victory at the Dubai International Stadium.