Henrikh Mkhitaryan was reportedly left stunned when Jose Mourinho opted to leave him out of the squad for Manchester United's Europa League group match against Fenerbahce on Thursday.
The Armenia international has not played since making his one and only start in the Red Devils' 2-1 defeat to local rivals Manchester City on September 10.
A thigh injury has contributed to the winger's time on the sidelines, but the 27-year-old is now fully fit and faces a battle to force his way into the first XI.
Mkhitaryan was spotted watching from the stands at Old Trafford as United went on to claim a 4-1 victory over Fenerbahce earlier in the week.
Mourinho recently claimed that Mkhitaryan needs to prove his fitness levels, but according to The Times, the player was left stunned when he did not make the squad on Thursday.
United signed Mkhitaryan from Borussia Dortmund in the summer transfer window for a reported £26m fee.