Ralf Rangnick is ready to turn to youth after revealing six first-team players have been ruled out of Thursday's Premier League meeting with Chelsea.
United's 3-1 defeat to Arsenal last week – a fourth straight away loss – effectively ended their chances of finishing in the top four and qualifying for the Champions League.
The Red Devils have four games remaining of another trophyless campaign before interim manager Rangnick is replaced by Ajax head coach Erik ten Hag.
Rangnick is expected to use his final month in charge to integrate some younger players into the squad, with Hannibal Mejbri and Shola Shoretire taking part in training this week.
And Rangnick's hand has been somewhat forced ahead of facing Chelsea as Harry Maguire and Jadon Sancho have been ruled out with a knee injury and illness respectively.
Fred, Edinson Cavani, Paul Pogba and Luke Shaw also remain out, while Aaron Wan-Bissaka will undergo a late fitness test on Thursday.
Asked if United fans will therefore get an opportunity to see the likes of Mejbri, Shoretire, Alejandro Garnacho and Alvaro Fernandez, Rangnick said: "It's possible.
"But we also have to be fair to those players – it has to be the right moment. They should have a chance to play well and perform well – we can't just push them into a game.
"We will try to play the best possible team of those players that are available.
"Right now, it seems we have 14 in our professional team without the youngsters that are available and probably three or four of those young players will be part of the squad."
United have used only four players aged 21 or under in the Premier League this season, while the average age of their starting line-up is 27 years and 200 days.
Only seven sides, opponents Chelsea among them, have named an older average XI in the English top flight this campaign.
While United fans are eager to see some more youth in the side, Rangnick's main focus is on finishing as high as possible before bowing out.
"We have four more games to play," he said at Wednesday's pre-match news conference.
"The next two games are at home at Old Trafford and we will try to get as many points and win as many games as we possibly can.
"In order to do that we need to play on the best level we possibly can. Chelsea is a good team but we know that if we play well it's possible to win the game tomorrow.
"I don't think it makes sense now to still speak and speculate about the Champions League places, we need to be realistic.
"Even if we win all four games it's not in our hands. What is in our hands is how we play and our level of performance. It's important to finish on the best possible note."
United have lost three of their last four league games – more than they had in their previous 18 – and are six points adrift of fourth-placed Arsenal having played a game more.
But Rangnick has warned his players they cannot afford to feel sorry for themselves as they attempt to salvage some pride in their remaining matches.
"If results are not going well, the morale, energy in the locker room isn't as good as it would be, but still we have to perform, this is what we're getting paid for," Rangnick said.
"It's important for the players, knowing the new manager, to show we are able to beat a team like Chelsea.
"This is our job, this is what everyone has to do and this is what we have been working for."
As focus slowly shifts towards the next transfer window, Rangnick suggested players will still want to join United even if they are not competing in the Champions League.
"It would be better if we played Champions League next season but this also affects other clubs; it's not only a problem Manchester United has," he said.
"The renewal of the contract of Bruno [Fernandes] shows this is an attractive club. With a new manager, new approach, this is still a massively interesting club.
"I look forward to helping Erik and everyone at the club to get the best and change the whole approach next season so Manchester United can be a top club."
United are unbeaten in their last eight home league games against Chelsea (W3 D5), keeping five clean sheets in that run since a 1-0 loss in May 2013.