Old Trafford insiders claim the Armenia midfielder is fed up trying to second guess his manager, as he was not even part of the travelling party for the impressive weekend victory at Arsenal.
Mkhitaryan has not started a game for United since November 5 and has been dropped for four of the last five outings, with Mourinho instead opting for Jesse Lingard, who has quickly repaid that faith with three goals in the last two games.
It is understood Mkhitryan is still training with the first-team squad but people close to the 28-year-old's camp have stated the player and his representatives are now seeking answers, ahead of the transfer window reopening next month.
They have duly noted the reports back in Germany that his former club Borussia Dortmund are closely monitoring developments and would be open to taking back a player who they begrudgingly allowed to quit for the Theatre of Dreams 18 months ago for £28m.
Mourinho has previously exhibited 'tough love' towards Mkhitaryan, in a bid to get the desired response, but the former Bundesliga Player of the Year is growing tired of being hung out to dry and is determined to bring the situation to a head.