Tyler Smith will join Doncaster Rovers on loan in January.
The paperwork will be rubber-stamped when the transfer window re-opens to allow the 20-year-old striker to further his development in SkyBet League One.
The Sheffield-born prospect spent the first half of the season on loan at Barrow in the National League, scoring 10 goals, before being recalled and he was on the bench for United's SkyBet Championship encounter against West Bromwich Albion.
Boss Chris Wilder comments: "Tyler did well at Barrow and we brought him back to see how far he has progressed. We think a step up to Doncaster will be great for his development and we'll continue to keep an eye on his progress."