Henrikh Mkhitaryan limped off with an apparent leg injury in Manchester United's Europa League round-of-32 second-leg clash with St Etienne on Wednesday.
The United midfielder gave Jose Mourinho's side a 1-0 lead with a near-post finish just after the quarter-hour mark, but came off in the 25th minute holding the back of his right leg.
The Armenia international was replaced by Marcus Rashford and is now a doubt for Sunday's EFL final clash with Southampton.
Mkhitaryan, who joined the club last summer...
Wayne Rooney has not been named in Manchester United's squad to face St Etienne in the Europa League on Wednesday despite returning to training with the club on Tuesday, while Luke Shaw also misses out.
Rooney, 31, had appeared to put himself in contention for the round-of-32 second leg after resuming training following a muscle strain.
However, the England captain has not been included in Jose Mourinho's 20-man squad for the clash, which United head into with a 3-0 advantage from the first leg.