Sir Alex Ferguson has confirmed that new Manchester United signing Gabriel Obertan will be out for at least three months.
The 20-year-old is thought to have picked up the problem at former club Bordeaux and is now not expected back until October.
The Red Devils boss admitted that he knew of the injury when he first lodged his interest in the Frenchman but still decided to go through with the transfer.
The news explains why the winger was not selected as one of United's 22-man squad for their pre-season tour of Asia earlier this week.
"Obertan has an injury that will keep him out for three months or maybe more," Ferguson said.
"We were aware of that at the medical but we're quite happy with the situation."
Ferguson has also revealed why fellow new signing Antonio Valencia and defender Nemanja Vidic were also absent from the party that boarded the plane to the Far East.
"Valencia didn't get his work permit," the Scot told the club's official website. "He had to go back to Ecuador to get a visa to come back into the country.
"It's one of these convoluted systems. It's frustrating but we have to accept it. He didn't get back to England until Monday and his fitness levels aren't ready yet. He'll join us in Munich (where United face two games in the Audi Cup from July 29th)."
Ferguson also confirmed that Vidic had returned to light training after injuring his ankle on international duty at the end of last season and he too should meet back up with the team in Germany.
"He's been doing some good physical running over the last few days but not enough to take part in games," he stated.