The Armenia international scored Arsenal’s equalising goal in their 2-1 loss to Manchester United on Sunday before Marouane Fellaini came off the bench to clinch the three points for Jose Mourinho’s men.
Mkhitaryan was in good form against his former club but was brought off in the 76th minute after suffering a knock to his knee.
The 29-year-old has been out of action with a knee injury recently and Wenger confirmed after the game that the playmaker had suffered a knock to the same area.
The Gunners boss also revealed that Mkhitaryan is a doubt for Thursday’s trip to Atletico Madrid along with David Ospina and midfielder Alex Iwobi.
Speaking at his post-match news conference, Wenger said: “I took off Mkhitaryan because he had a little knock on his knee again, on the same knee – we could see that just looking at him in the dressing room.
“Ospina has a rib problem and Alex Iwobi has a hamstring problem, so we’ll see how well everyone recovers. Thursday will come very quickly.
“At the moment, no [they are definitely not out for Thursday], but we’ll have to monitor them over the next 48 hours. We’ll know more on Tuesday.”
Arsenal head into the game looking to claim their spot in the Europa League final as they bid to secure their place in the group stage of the Champions League for next season by winning the competition.
The Gunners were held to a frustrating 1-1 draw by Atletico Madrid in the first leg of the semi-final tie in London last week.
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