The German was absent for the Gunners’ dramatic win over Tottenham in the first north London derby of the season on Sunday having previously missed his side’s Europa League clash with Vorskla Poltava in Kiev.
In Ozil’s absence, Arsenal have flourished in a formation with three centre-backs and it remains to be seen whether the midfielder would slot straight back into the side when fit again.
Speaking in his pre-match press conference on Monday afternoon, Emery revealed that Ozil is still training by himself as he works his way back to full fitness.
“Today he was working alone, I don’t know if he’s OK for Wednesday,” Emery said.
“I said yesterday he’s had backache since last Tuesday. He couldn’t play in Kiev or yesterday.
“At the moment, I don’t know if he can play in Manchester.”
Emery’s side are currently eight points clear of Wednesday’s opponents United and moved into the top four having registered another three points against Spurs.
United could only manage a draw against Southampton on Saturday and are languishing in seventh place in the Premier League table.
But Emery says his side will not be taking United lightly given the quality they have in their team.
“It’s not normal where they are in the table,” the Arsenal boss added.
“They have a lot of potential and experience with the coach, who has a big experience in the Premier League, in Europe, in world football.
“We respect them a lot individually and collectively, and we know it’s a very difficult match away.”
Emery has gained plenty of admirers during his time at Arsenal so far, one of whom is United midfielder Juan Mata, who played under the Spaniard at Valencia and recently described him as a “special” coach.
The Arsenal boss responded on Wednesday by saying:
“He’s a very good player and a very good person, I had a very good experience with him in Valencia at the beginning of his career.
“Then he came to the Premier League and I think he’s a very important player here, first at Chelsea, then at Manchester United.”