Zlatan Ibrahimovic has been warned against making an early comeback for Manchester United by surgeon Dr Freddie Fu, who operated on his knee in May.

Ibrahimovic has not played since damaging knee ligaments in United's Europa League quarterfinal against Anderlecht in April, but after signing a new one-year deal in the summer, has hinted he could return soon.

United boss Jose Mourinho has been more cautious and suggested the 35-year-old will not be ready until January, despite including him in the squad for the Champions League group stage which runs from September to December.

"I have no worry about his injury as it always takes time to fully recover," Dr Fu, chairman of the Department of Orthopaedic Surgery at the University of Pittsburgh School of Medicine, told the South China Morning Post.

"In fact the EPL has just started and I am sure Manchester United would not need the player urgently for any crucial game either in the league or European competitions.