Michael Carrick could be out for up to a month
Published 24/01/2014 | 10:15
The England midfielder was expected to be out for two weeks, but initial tests have shown the injury to be more serious, British media said.
The deep-lying playmaker had only just returned from a six-week layoff following an Achilles tendon problem and his absence is a further blow to embattled manager David Moyes, who is already without injured strikers Wayne Rooney and Robin van Persie.
United are currently seventh in the Premier League, 14 points adrift of leaders Arsenal.