Sir Alex Ferguson has revealed that the 23-year-old had been playing through the pain barrier during the Champions League win over Braga which aggravated the problem
Manchester United manager Sir Alex Ferguson has revealed Shinji Kagawa will be sidelined for up to a month with a knee injury.
The Japanese international was taken off at half-time during United's 3-2 Champions League win over Braga on Tuesday night after aggravating the problem.
Kagawa will now miss Sunday’s trip to face Chelsea, along with the visit of Arsenal on November 3 and is a doubt for the Champions League trip to Galatasaray 17 days later.
"It's a similar [knee] injury to the one Ashley Young had," Sir Alex told reporters.
"He's going to be out for three to four weeks. Playing on with the injury didn't help the situation for him."
Kagawa has made a steady start to his Old Trafford career, scoring two goals in six games in the Premier League, and should be fit in time to play a part in his first Manchester derby on December 9.
Sir Alex boss also revealed that Chris Smalling is back in training and he hopes fellow defensive partner Phil Jones will step up his rehabilitation in 10 days’ time.
He added: "Smalling is back training on the football side of things. Phil Jones will hopefully start full training a week on Monday."