Luke Shaw is due to have medical at Manchester United ahead of a proposed £30 million move.
Shaw, 19, should complete his transfer before departing on holiday having featured for England at the World Cup in Brazil.
It is believed Shaw is due to have a medical at the club's Carrington training ground on Thursday evening.
The left-back - regarded as United's long-term successor to Patrice Evra - will become the club's second summer signing after Ander Herrera completed his £29m move from Athletic Bilbao.
Shaw made his first competitive England start against Costa Rica on Tuesday
Evra's contract expired this summer yet a clause triggered a one-year extension while Alexander Büttner, United's reserve left-back, is on the verge of joining Dinamo Moscow.
Southampton rejected a £27m bid from United last month and the protracted transfer was put on hold after manager Mauricio Pochettino joined Tottenham.
However, following Ronald Koeman's appointment as Pochettino's predecessor last week the Saints are on the brink of sanctioning the sale of another outstanding academy graduate.
Shaw made his England debut in March and started in Tuesday's dead rubber with Costa Rica, having dislodged Ashley Cole for the second left-back spot behind Leighton Baines.
He was named in the PFA Team of the Year for last season and despite interest from boyhood club Chelsea his parents advised him to join United instead. Shaw told Southampton on the final day of the season - in which they drew against United - he wanted to move to Old Trafford.
Former United manager oversaw much of the work of Shaw's transfer and also alerted the club that Herrera's buyout clause was due to increase in July. Van Gaal scuppered a proposed deal for Bayern Munich midfielder Toni Kroos yet shares his predecessor's admiration of Herrera and Shaw.
