The two centre-backs leave manager Erik ten Hag with a problem to be solved, although Maguire – who sustained his injury during his international service with England – has recently lost his basic sport.
Varane stumbled out of the 6-3 hammer in the Manchester derby after a blow to his ankle in the first half and was replaced by Victor Lindelofwho will replace along with Lisandro Martinez on Thursday evening.
Aaron Wan-Bissaka and Donny van de Beek remain unavailable, and Ten Hag says he cannot provide a prognosis about the pair.
“They are not available for tomorrow,” said Ten Hag. “In the case of Rapha, I’m hopeful (he will be available soon). Harry will need a little longer and I can’t predict the other two.”
Cristiano Ronaldo should start, although returning Anthony Martial is pushing for a start.
Phil Jones, Axel Tuanzebe and Brandon Williams are absent for a long time.
Manchester United’s predicted lineup: DeGea; Dalot, Lindelof, Martinez, Shaw; Casemiro, Eriksen; Antony, Fernandes, Martial; Ronaldo
Europa League squad (available players): De Gea, Heaton, Dubravka, Lindelof, Martinez, Malaysia, Dalot, Shaw, Fernandes, Eriksen, Fred, Casemiro, McTominay, Iqbal, Ronaldo, Martial, Rashford, Antony, Sancho, Pellistri, Elanga, Garnacho