Anthony Martial and Jesse Lingard will be out of action for between two and three weeks after limping out of the Champions League defeat by Paris Saint-Germain.
It means that both players will miss Monday’s FA Cup fifth round clash at Chelsea and the Premier League clash at home to Liverpool a week on Sunday.
They are also likely to be unavailable for the league games against Crystal Palace and Southampton and, possibly, the second leg in Paris early next month when United try to overturn a two-goal deficit.
Lingard went off at the end of the first half against PSG with a hamstring problem, and Martial followed at the half-time interval with a recurrence of a groin problem.
Caretaker manager Ole Gunnar Solakjaer confirmed: ‘I think they will be out for two to three weeks. Then you’re looking at it being Mason Greenwood’s time to step in and he’s out for couple of weeks. That’s the way sometimes the luck goes.
‘Anthony and Jesse have done really well for us, they’re vital. Then again, with Romelu (Lukaku) and Alexis (Sanchez), they’ve got different skill sets and will be able to show what they can do, so need to gel a team together for Monday.’
Solskjaer has challenged his players to bounce from his first defeat in 12 games in charge when they take on Chelsea. ‘You don’t panic because you’ve lost a game,’ he added. ‘You don’t change everything. It doesn’t change the mind set at all.
‘I hate losing games, the boys hate it. They’ve been down, but there’s no point dwelling on it. There are big games with good teams coming up and we need to dust ourselves down.
‘You’ve got to bounce back at this club. You always have challenges and away against Chelsea is tough. We know there was a spell against PSG, seven or eight minutes, we lost our way apart from that we weren’t too bad.
‘We need to keep working at the way we play football. We want to go down to Chelsea, we want to have Liverpool here and impose ourselves on those games. There are quite a few other teams with injuries so you have to adapt to that.’
‘We beat Arsenal and Liverpool as well,’ said Solskjaer. ‘We did it the hard way then and we will have to do it the hard way this year. We’re looking forward to it.
‘I went to see them (in a 6-0 defeat) against Manchester City. City were clinical but Chelsea have got some fantastic players and could have scored two or three in the first half.
‘They could’ve been two or three up (in a 4-0 defeat) at Bournemouth. It’s those little things that decide games.’