Morrison, who helped Queens Park Rangers win promotion to the Premier League last season, was diagnosed with the condition during pre-season testing back at his parent club West Ham United.
The operation was completed without complications, and the 21-year-old will now undergo rehabilitation before he is expected to return to training in a few weeks when the first-team squad return from New Zealand.
Morrison scored five goals in 22 matches for the Hammers last season, including the club’s goal of the season in their 3-0 victory over Tottenham Hotspur last November. He joined QPR on loan towards the back end of the season, scoring six goals to help the Hoops win the Championship play-offs.
He will be hoping to be back in action and included in Gareth Southgate’s England Under-21 squad for the final European Championship qualifiers against Lithuania and Moldova in September.
