Leeds are putting the finishing touches to a deal which will make Borthwick-Jackson their 10th first-team signing of the summer and add cover on the left side of Thomas Christiansen’s defence.
United have been short of options in that area since losing Charlie Taylor to Burnley but Borthwick-Jackson’s arrival will provide competition for Gaetano Berardi.
The transfer is also set to clear the way for young Leeds left-back Tyler Denton to join League Two club Port Vale on a season’s loan next week.
Denton signed a new three-year deal at Elland Road yesterday but is unlikely to feature under Christiansen this season following United’s move for Borthwick-Jackson.
Leeds have been monitoring the 20-year-old for the past month and stepped into sign him after Manchester United agreed to sanction his departure to the Championship for the second time in two years.
Borthwick-Jackson was loaned to Wolverhampton Wanderers last season but played only seven times.
Leeds head coach Christiansen confirmed his interest in Borthwick-Jackson ahead of he defender’s medical yesterday, saying: “I’ve seen him a few times. He’s a very good player and homegrown which is very important.”