The Japan international moved to the Old Trafford outfit from Borussia Dortmund this summer, and has initially impressed for the Red Devils in starting from wide and as a second striker.
However, Kagawa is a major doubt for this weekend’s Premier League game against Wigan after picking up a back injury whilst on international duty.
The Asian attacker pulled out of Japan’s game against Iraq on Tuesday just before kick-off, after complaining of a back twinge picked up in training.
However, Kagawa has vowed to toughen up to show longevity for Sir Alex Ferguson’s men.
“I’ve realised that I need to limber up and strengthen my body,” he is quoted as saying in The Daily Mail.
“There are some tough games coming up. This injury may be due to travel and fatigue but I can get by if I take good care of my body.”
Wayne Rooney is ruled out of United’s game this weekend, whilst Kagawa and Robin van Persie are also doubts after international duty.
By Gareth McKnight