Manchester United face an anxious wait over the fitness of Paul Pogba after their world-record signing limped out of Thursday's Europa League defeat at Fenerbahce.
Pogba was forced off just 30 minutes into United's 2-1 loss in Istanbul, appearing to injure his thigh in a tackle with Brazilian midfielder Souza.
The Frenchman played on after initially punching the ground in frustration but soon signalled to the bench that he was unable to carry on and was subsequently replaced by Zlatan Ibrahimovic.
Pogba will be assessed back in Manchester but appears doubtful for Sunday's trip to Swansea, where manager Jose Mourinho will serve a one-match touchline ban.
Mourinho was already facing a reshuffle for the Premier League clash with midfielder Ander Herrera suspended following his dismissal in the goalless draw against Burnley at Old Trafford last weekend.
His midfield options now include Morgan Schneiderlin, who was hauled off at half-time against Fenerbahce, Michael Carrick, the out-of-favour Marouane Fellaini and the previously exiled Bastian Schweinsteiger.
Problem persists in defence for United with Antonio Valencia (arm) and Eric Bailly (knee) also out.