Louis van Gaal has confirmed defensive starlets Paddy McNair and Tom Thorpe will be part of his Manchester United squad for the visit of West Ham United on Saturday.
United have been beset by injuries during the opening two months of the season and are without Phil Jones, Chris Smalling and Jonny Evans, who have all been ruled out with knocks.
With Tyler Blackett suspended after his red card against Leicester City last week and occasional stand-in centre half Michael Carrick still completing his recovery from an ankle injury, summer signing Marcos Rojo represents van Gaal's only option in his first-team squad.
It had been thought that the Dutchman may turn to his versatile compatriot Daley Blind to drop back into defence, but the United boss insists that isn't an option.
When asked about McNair, 19, and Thorpe, 21, van Gaal told MUTV: "They are in the squad. That is why we have a youth education. It was also our policy [to utilise the youth squads] and always the policy of the club too.
"I do not like having too many defenders or left-footed players in defence. I think always of balance so [instead] I have to pick up a right-sided central defender from the youth education. Normally I am always doing things like that. I have already said that we have a lot of vacancies when you buy only six players and let 14 go."
United's persistent injury problems in defence have again raised questions over the club's summer transfer policy, where Rojo was the only addition at centre-half despite the departures of Nemanja Vidic and Rio Ferdinand.
And van Gaal admits that the current situation, which sees nine players unavailable through injury – 10 including the suspended Blackett – is "surprising", something he has never experienced in his 23 years in management.
"I am a coach who has a lot of experience and I believe I was never in this situation before, so it is surprising me" the former Ajax and Barcelona coach said.
"I am evaluating myself and my staff and also the players and what is wrong. But I cannot imagine what we are doing is at another level to [what I did at] my former clubs. So I have already adapted to a certain level that I think we can play during a game, but I cannot train at a lower level."