Aaron Wan-Bissaka is set to be out for several weeks after picking up an injury against Brighton, while Maguire has not travelled to Germany after suffering an issue in training.
“He had some complaints and we have to see how bad it is,” Erik ten Hag said when discussing Maguire in his pre-match press conference.
“So he finished training but it was not good enough to travel.”
Raphael Varane and Mason Mount are both back in training but are not in the group that flew out to Munich, while Sofyan Amrabat has been working away from the first-team squad and is not yet ready to make his debut.
The diamond shape did not work against Brighton, so United have reverted to a more familiar 4-3-3 shape.
Subs: Bayindir, Heaton, Vitek, Evans, Gore, Hannibal, McTominay, Forson, Garnacho, Martial
Time and date: 8pm, Wednesday September 20, 2023
Venue: Allianz Arena