Arsenal plan to meet with Uefa to express their fury after Henrikh Mkhitaryan decided against playing in the Europa League final over security fears.
The Armenian's safety was a concern because of the dispute between his country and Azerbaijan, the host nation of next week's fixture between the Gunners and Chelsea.
Despite receiving assurances aimed at allaying those fears, Mkhitaryan has chosen not to travel to Baku following discussions with the club and his family.
Arsenal boss Unai Emery said he respected the "personal" nature of Mkhitaryan's decision, but conceded it was "bad news" for his team.
But Arsenal managing director Vinai Venkatesham branded the situation "unacceptable" and revealed the club would make the full extent of their anger known to the governing body.
He was quoted as saying by a number of national newspapers: "I struggle to find words for how strongly I feel. We feel it's unacceptable."