The 20-year-old, who has already had a spell in South Yorkshire with Barnsley this season, has signed on an emergency loan deal.
The England Under-19 international could make his debut in Saturday's League One clash at Leyton Orient and becomes the second arrival of the day at Hillsborough after Keith Treacy joined from Burnley on a similar deal.
Ranger has had troubled times on Tyneside this season, spending more time in Crown Court than he has on the football field.
Could this be the time for him to bump-start his career?
He has the ability - shame he hasn't got two brain cells to rub together!