The striker joined Arsenal in a club-record deal from Borussia Dortmund in January but is cup-tied in the Europa League.
Arsenal defeated AC Milan 2-0 in the first leg of their last-16 clash last week and can progress to the quarter-finals when Milan travel to the Emirates this Thursday.
The Gabonese will not be involved, however, and he has revealed his ‘frustration’ at not being able to help his team in Europe.
He told talkSPORT, “I am really frustrated because the rules are a bit… I don’t know how to say in English, but I am disappointed because I can’t help my team. That’s life. I have to deal with it.”
The Gabonese international scored on his debut for the Gunners in the 5-1 thrashing of Everton last month, but then went three games without a goal.
He added, “When I was in Dortmund, I was playing every three days but now I play once a week or have a long time between games. It is not easy.”