Arsenal confirmed last week that the midfielder won't be available to play in the Europa League final between Arsenal and Chelsea in Baku.
The ongoing conflict between Azerbaijan and Armenia, which started in 1994, meant that Arsenal chose not to take their player to the final as a safety precaution.
Even so, the 'Gunners' wanted to show their support for the Armenian by wearing t-shirts with his name on for the warm up - a gesture that UEFA have blocked.
The European governing body has very strict regulations in terms of what teams are allowed or not allowed to wear, meaning Arsenal players will not be allowed to show their support for Mkhitaryan before the game on Wednesday.