The 24-year-old midfielder starred for United in the 5-1 whipping of Leeds in their opening Premier League fixture but was only able to play a bit part role as a substitute in the 1-1 draw with Southampton last Sunday.
United will hope the Scottish international makes significant progress during the upcoming international break ahead of what will be a hectic club schedule following it.
"Scott has undergone surgery for an ongoing groin injury that was causing significant pain when playing," said the club in an official statement.
"Having tried all other treatment options in pre-season, surgery was deemed necessary to resolve the issue.
"We hope to have him back soon."
United have three league games in September -- against Newcastle United, West Ham United and Aston Villa.
They play West Ham again in the League Cup and begin their Champions League group stage campaign.
