Sancho was dropped for United’s 3-1 defeat to Arsenal earlier this month for what United manager Erik ten Hag deemed poor performances in training.
The 23-year-old responded by posting on social media that he had been made “a scapegoat for a long time”.
In a statement, United said: “Jadon Sancho will remain on a personal training programme away from the first-team group, pending resolution of a squad discipline issue.”
Sancho was considered one of the brightest young talents in European football when he joined United for £73 million ($91 million) from Borussia Dortmund two years ago.
But he has struggled to live up to that price tag at Old Trafford, scoring just 12 goals in 82 appearances.
Ten Hag has proven to be a strict disciplinarian even with some of his biggest stars at Old Trafford.
Cristiano Ronaldo’s second spell at the club was cut short after he criticised the former Ajax manager in a television interview, while Marcus Rashford was benched for a match last season after arriving late to a team meeting.
Sancho’s absence compounds a miserable start to the season for United on and off the field.
Ten Hag’s men have lost two of their opening four Premier League games.
United are currently without Brazilian winger Antony after he was given a leave of absence to fight allegations of domestic abuse made by his former girlfriend.
United also received criticism for their handling of Mason Greenwood, who has joined Spanish side Getafe on loan, after agreeing with the player that his career at the club could not continue.
The 21-year-old had faced charges including attempted rape and assault, but prosecutors announced in February this year that the case had been dropped after key witnesses withdrew and new evidence came to light.
Initial reports suggested United were planning to reintroduce the striker to the team before a public outcry sparked the decision to part ways.
Meanwhile, protests against United’s owners, the Glazer family, remain a common occurrence at home matches as a process for the Americans to sell the club appears to have ground to a halt.
AFP
