Man Utd's Kagawa says injury is 'good lesson'

TOKYO (AFP) - Manchester United star Shinji Kagawa has vowed to take better care of himself after being sidelined by a back injury that he said may have been caused by "travel and fatigue".

Kagawa, forced out of Japan's 1-0 win against Iraq on Tuesday by a minor back strain, admitted he needed to strengthen his body to prevent further problems. It is unknown when he will return for his new club.

"It may be due to travel and fatigue," Kagawa told reporters on Wednesday, before boarding the 12-hour return flight to England. "I can get by if I take good care of my body," he added. "I've learned a good lesson from this."

The attacking midfielder felt a "twinge" in his back during training and despite treatment, he was eventually withdrawn from Japan's team just before kick-off in Saitama. Kagawa, 23, has not been known to suffer any back problems since starting his professional career in 2006, with J-League side Cerezo Osaka.