United keeper Bailey Peacock-Farrell had joined York City on a one-month loan deal.
The rules governing the transfer window prevented Peacock-Farrell from switching to another EFL side until January, barring a short-term switch through special dispensation, but he was free to drop down into non-league football and the youngster has been pushing for games after a recent call-up to the Northern Ireland squad.
York's newly-appointed manager Martin Gray said: "He's been very highly recommended".
"He's big, 6ft 4in, and very athletic".
"He has got a massive future ahead of him but he needs some real senior football now and, hopefully, we can give him that opportunity".
Born in Darlington, Peacock-Farrell spent seven years at Middlesbrough's youth academy before joining Leeds in 2013.
He made his full Leeds debut, aged just 19, in a 1-1 draw against Queens Park Rangers in the Championship eighteen months ago.
There is little chance of a breakthrough at Elland Road in that time so a prolonged temporary switch will surely be welcome if all parties can come to an agreement in due course.