Manchester United defender Phil Jones has suffered a setback in his return from injury, according to the Daily Mail.
The 20-year-old, who has missed the start of the Premier League season due to back spasms, was seen leaving the Red Devils' Carrington training ground on crutches on Thursday.
Jones made 37 appearances last season following his £16.5m move from Blackburn Rovers.
He also made his international debut for England in a 2-2 draw with Montenegro in October.