Manchester United defender Luke Shaw has been ruled out for four weeks with a hamstring injury.
The England international, 19, joined from Southampton for £27m in June.
He featured in all five games on United's summer tour of the United States, but did not play in Tuesday's 2-1 victory over Valencia at Old Trafford, their final pre-season friendly.
They begin the Premier League season at home to Swansea on Saturday.
|The games Luke Shaw looks set to miss|
|Sat 16 Aug: Swansea (h)|
|Sun 24 Aug: Sunderland (a)|
|Tues/Wed 26/27 Aug: Capital One Cup second round|
|Sat 30 Aug: Burnley (a)|
|Sun 14 Sept: QPR (h)|
|All games Premier League unless stated|
Shaw, who has been given squad number three for the new campaign following Patrice Evra's departure to Juventus, was expected to be manager Louis van Gaal's first-choice left wing-back.
Van Gaal used 20-year-old Reece James in the role in the US and against Valencia.
James has not played a competitive game for United. His only two professional appearances came during a loan spell at Carlisle last season which was cut short by injury.
Shaw, who made his England debut in March, won the last of his three caps in the World Cup against Costa Rica in Brazil this summer.
He was put on a special fitness programme after Van Gaal criticised his fitness in July.