Manchester United legend Paul Scholes expects major changes for this weekend's game against West Ham United.
The Red Devils failed to keep up with the pace of Real Madrid on Tuesday, especially defender Victor Lindelof who struggled in defence.
But Mourinho's men will be eager to kick off their Premier League campaign with a win when they host Slaven Bilic's side.
"I think [Eric] Bailly will probably come into as centre half for probably [Victor] Lindelof, who will take a little bit of time to settle from what we've seen from pre-season games," Scholes told BT Sport.
"Possibly the left-back as well, will [Daley] Blind come in with the game at Old Trafford?
"He's better on the ball than [Matteo] Darmian although Darmian is a better defender.
"I think the positions that are up for grabs are [Henrikh] Mkhitaryan, [Jesse] Lingard who are playing tonight [against Real Madrid].
"They've got so many people in those positions who are capable of coming into that team and are probably a bit quicker than those two as well and will add pace and goal threat to the team.
"You're talking [Marcus] Rashford, [Anthony] Martial, [Juan] Mata when he comes in does really well, he seems to score goals.
"I think the reason he is playing them two tonight is because they might join in with the midfield a bit more than a Rashford or a Martial."
