The Germany international missed sessions on Monday and Tuesday and was in bed with ‘sickness’ according to Wenger.
The Gunners take on Ostersunds at the Emirates on Thursday and have a 3-0 aggregate lead going into the second leg of their last-32 Europa League clash.
Wenger had planned on playing the German against Ostersunds on Thursday but revealed the German is struggling with illness and was only able to participate in today’s session for the first time this week.
‘Mesut was sick until today,’ revealed Wenger.
‘It was his first training session today. He was in bed on Monday and Tuesday with sickness.
‘I would certainly have played him but because he was sick he will have to work hard tomorrow and he will not be involved.’
More: Arsenal FC
Wenger’s likely to field a weakened side against the Swedes on Thursday and will have one eye on Sunday’s clash against City at Wembley.
Henrikh Mkhitaryan, ineligible due to his participation with Manchester United in the competition earlier this season, is unable to play against City and will therefore start against Ostersunds.