Luke Shaw is set for a spell on the sidelines after Manchester United confirmed the left-back would miss the start of the Barclays Premier League season with a hamstring injury.

Shaw, who joined the club from Southampton in June for £27m, faces a four-week lay-off, meaning he will miss United's opening league game against Swansea on Saturday.

The 19-year-old, who became the world's most expensive teenage footballer when he made the move to Old Trafford, could also miss further Premier League games against Sunderland and Burnley.

A statement on Manchester United's official website read: "Luke Shaw has suffered a hamstring injury and will miss the opening game of the season against Swansea City on Saturday.

"The England international, a summer signing from Southampton, is likely to be sidelined for around four weeks.

"Shaw sat out the friendly victory against Valencia at Old Trafford due to the problem and faces a wait before making his competitive debut for the club."

Shaw made his United debut against LA Galaxy in July during their summer tour of North America.

Earlier on Wednesday, the Red Devils confirmed that Shaw had been given the number three shirt for the forthcoming season, after it had been vacated by Patrice Evra's departure for Juventus.