Jadon Sancho will spend season on loan at Chelsea in deal which includes an obligation to buy if targets are met; England international cost United £73m but spent second half of last season on loan at Borussia Dortmund.
Sancho has scored 12 goals and contributed six assists in 83 games for United since signing from Dortmund for £73m three years ago.
Sancho – who has 23 caps for England – fell out of favour at United last season after a public disagreement with Ten Hag.
The forward was welcomed back into Ten Hag’s squad this summer but his only action so far this season was a brief appearance from the bench in the Community Shield.