The game is the first leg of their round-of-32 tie.
The match is Sociedad’s home tie but is being played in Turin, due to travel restrictions imposed by the Spanish government.
Old Trafford is set to host the return fixture as planned, and away goals apply as normal.
Here is everything you need to know.
Real Sociedad vs Manchester United kicks off at 5.55pm GMT.
The match will be broadcast live in the UK on BT Sport. Subscribers can stream online via the BT Sport website and the BT Sport app.
Paul Pogba remains unavailable through injury, as does Phil Jones. Ole Gunnar Solskjaer may rotate some of his team as United fight on various fronts.
Manchester United: Henderson; Wan-Bissaka, Bailly, Maguire, Telles; Fred, McTominay; Greenwood, Fernandes, Rashford; Cavani
Sociedad’s form has tailed off dramatically in the past few weeks having topped the Liga table earlier in the season, but they have now won their last two. United should have enough to cause plenty of problems, despite their own stutters. Real Sociedad 1-1 Manchester United.