The Whites have been handed a major injury blow ahead of the crucial fixture at Old Trafford.
Daniel Farke’s men reached the FA Cup semi-finals after beating West Ham United on penalties, but the victory came at a cost.
Anton Stach picked up a ligament injury following a clash with Max Kilman and was replaced by Brenden Aaronson after 39 minutes.
Leeds came close to victory after goals from Ao Tanaka and Dominic Calvert-Lewin, but the hosts struck twice in injury time to take the game to extra time and penalties.
Lucas Perri starred in the shoot-out, making two vital saves to earn Farke’s side a memorable win.
It is unclear at this stage how serious Stach’s injury is, but he is unlikely to feature when Leeds take on United next week.
Stach has been a key first-team player this season. The midfielder has started 25 Premier League games, bagging four goals and three assists.
They drew 1-1 with United in the reverse fixture in January. However, they are expected to face a tougher challenge this time with the Red Devils transformed under Michael Carrick.
Stats from Transfermarkt.