The veteran defender was forced off in the first half during Wednesday’s Champions League defeat to FC Copenhagen in the Champions League.
Evans was brought in as cover during the summer transfer window but has grown in importance in recent weeks, starting the last five League games.
“So we don’t have, in this moment, the full assessment and all the details but, tomorrow, he is out,” said Erik ten Hag on Friday.
“I can’t say [if he can go away with Northern Ireland] as we don’t have the finished assessment.”
That means Ten Hag must decide on whether to bring Raphael Varane back into the starting lineup alongside Harry Maguire.
Marcus Rashford starts too after recovering from the knock that ruled him out of the late win over Fulham last weekend, even with his Champions League suspension in mind.
United remain without Amad Diallo, Tyrell Malacia, Casemiro, Lisandro Martinez and Luke Shaw for the visit of the Hatters, who recently earned a more than creditable draw against Liverpool.
“He started the season,” he said.
“Then he got injured, so that is the worst moment for a new player to get injured because it stops the integration process and that was a setback for us all. Now we have to find his place back."
Injured: Casemiro, Amad, Evans, Shaw, Malacia, Martinez
Time and date: 3pm GMT on Saturday, November 11, 2023
Venue: Old Trafford