George Long will be available for selection when United host Gillingham at Bramall Lane on Saturday, boss Nigel Clough has revealed.
The goalkeeper is currently away with England's U21s, who face Finland in a Euro Championship qualifier at stadium:mk on Thursday, but will return to Shirecliffe on Friday morning and train with United ahead of the weekend's clash.
Clough commented: "We have got the same arrangement with George (Long) as, I am told, the club had with the FA and Gareth Southgate last month for the game at Coventry City.
"George will head back to Sheffield straight after England's game on Thursday night and be available to train with the rest of the lads on Friday morning.
"We thank the FA and Gareth in particular for this understanding because obviously George is a crucial member of the squad.
"After our fixture on Saturday he will rejoin the England squad for their second qualifier against San Marino on Tuesday.
"We have been impressed with the way George and Harry (Maguire) have conducted themselves, given they are both at the tender age of just 20.
"They are two lads who we should be aiming to build around in the future. Both have matured very quickly because of the exposure they have had to deal with."