Following previous spells with Huddersfield, Cardiff and Watford, the 21-year-old is Keith Hill's 10th signing for the new season.
"Drinkwater is a few years ahead of the younger lads in his development," Reserves boss Warren Joyce told ManUtd.com. "He's had two or three loan spells. Two have been successful but there's one that's not been due to injuries hampering his loan appearances.
"But he has developed and is a lot physically stronger. He's done a lot more things than the youth team boys and that's why we're getting him out on loan again."