Antonio Valencia will miss the start of the Premier League season after picking up a suspected torn calf muscle against San Jose Earthquakes.
With summer signing Diogo Dalot also recovering from injury, Manchester United boss Jose Mourinho revealed that Ashley Young has been asked to return early from holiday to deputise.
Young played five games for England as they reached the semi-final of the World Cup, although he sat out the third place play-off on June 14.
Mourinho said: ‘Valencia is injured and he will be injured for the beginning of the Premier League. Diogo Dalot is also in the recovering phase, he will not be ready for the beginning of the Premier League.’
He added: ‘Ashley Young is a possibility to play right back but he is on holiday. I don’t know if he fancies to be back for that and put himself to be available for the team or stay on holiday.’
Mourinho also believes Victor Lindelof could fill in, although the Sweden centre-back is also on holiday after his country lost to England in the quarter-finals.
He said: ‘Victor Lindelof is a possibility. He is not a right back but he’s a possibility. He starts training next Monday and I will send people to Manchester to train with Victor. It makes no sense for him to come to the US.’
Another solution would be retaining the services of Matteo Darmian, although the full back has made it clear he wishes to leave for regular game time.
Mourinho admitted he would not stand in Darmian’s way if an acceptable bid was made.
He said: ‘Matteo wants to leave, and I think when a player wants to leave, if the right offer arrives you have to try to be human and let the player follow his instinct,’ said Mourinho.
‘But not at any price and until now the offers we got for Matteo are not even close to being accepted.
‘So if Matteo leaves, he leaves because the right offer arrives and if he stays, yes you are right, he can be important for us.’