The Red Devils have a busy fixture list approaching, facing Wigan at home on Saturday before taking on Galatasaray at Old Trafford and travelling to Anfield to face fierce rivals Liverpool the following weekend.
Kagawa said: "It's not a serious injury and I don't think it will keep me out for long. I can walk without any problem but if I put strain on it it still hurts."
"I underwent treatment for as long as possible before the match."
Japan boss Alberto Zaccheroni had withdrawn Kagawa in the previous game due to his frustration with the player's apparent "showboating", but confirmed that injury was the reason he had been left out of the match squad. "I waited until the afternoon to see how his condition was but there's no way I can put a player on the pitch who is not at 100 per cent," said the Italian.