Erik ten Hag named his 22-man squad due to travel to Moldova today and the in-form striker sits out the trip having not taken part in training on Wednesday morning.
Anthony Martial, Donny van de Beek and Aaron Wan-Bissaka also miss out while there is a place for Luke Shaw, who recently returned from a foot injury.
Youngsters Alejandro Garnacho, Luke McNeil, Zidane Iqbal and Radek Vitek make the squad with Ten Hag able to pick a stronger than expected squad given the Premier League postponements either side of Thursday’s game.
United suffered defeat in their opening group match last week, at home to Real Sociedad.
Full Man United travelling squad:
GK: De Gea, Heaton, Vitek.
DEF: Lindelof, Maguire, Martinez, Malacia, Varane, Dalot, Shaw.
MID: Fernandes, Eriksen, Fred, Casemiro, McTominay, Iqbal.
FWD: Ronaldo, Antony, Sancho, Elanga, Garnacho, McNeill.