Ole Gunnar Solskjaer insists it's unfair to blame him if he puts out a weakened team against Leicester at Old Trafford on Tuesday night.
Having fielded a strong line-up at Aston Villa on Sunday, Solskjaer is expected to make wholesale changes against Leicester before recalling more of his first-choice players at home to Liverpool 48 hours later.
The issue has raised concerns over the integrity of the Premier League with Leicester and Liverpool among the clubs battling for a top-four spot.
However, Solskjaer believes he has no choice but to use all the resources at his disposal after United were handed a run of three games in five days by the Premier League straight after playing in the Europa League semi-final in Rome last Thursday.
'Talking about integrity in the league and stuff, don't blame me when I have to make changes because I have to,' he said. 'It's not safe for them to play all four so I have to prioritise.
'I wish I could have said "let's go full out in all the games" but it's impossible. That's the hard bit for me, knowing if I do play this 11 on Tuesday and then again on Thursday it's impossible. I run too much of a risk in injuring them.'
Solskjaer will wait until Tuesday before deciding on his team after he has assessed the players, but expects to include some youngsters in the squad.
'They're in contention, definitely,' he added. 'They're in the first-team squad they're training with us every day, so I would think that some of the young boys will get an appearance definitely.
'If it's coming on towards the end or it's starting I don't know because I don't know how the players will be on Tuesday when we see them.
'We will sit down with the sports scientists on Monday. We can have a theoretical team now but we'll have to see how they react when they come in and then pick a team Tuesday afternoon.'
Mason Greenwood is one of the players Solskjaer may have to protect after the teenager played 90 minutes against Roma and more than an hour at Villa where he scored the second goal in a 3-1 win.
'Thursday night he worked his socks off and then he's going again and he's tired,' said Solskjaer. 'His body is not really filled out yet and he might not be ready for all of these games, but he's got something special.
'The kid just turns the game around in one split second and the goal (at Villa) was excellent. I'm delighted that he's got back to his goal scoring best.
'I can say that Mason is learning all the time. He's learning on the job which isn't easy. He's had to bear a lot of responsibility and he's popped up with so many important goals for us.'