British newspapers including The Guardian and The Mirror report on their websites that Hargreaves felt his shoulder pop out of its joint in training on Friday.

Hargreaves has played just six minutes of first-team football since September 2008 because of knee problems.

His most recent comeback attempt ended in November when he tore his hamstring against Wolverhampton Wanderers and limped off early.

The 30-year-old midfielder’s contract with United expires at the end of the season.