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.
Australia hold on to beat South Africa with 11 men in Perth
Czechs down Ukraine to claim 12th Billie Jean King Cup crown
Fernandez beats Gibson to win Singapore Open title
World champions Spain defeat England at Nations League thriller
Saudi Arabia reach Gulf Cup semis as Iraq win thriller
