The midfielder appeared in the first half of Japan's 1-0 win over United Arab Emirates in Niigata on Thursday, a warm-up for Tuesday's World Cup qualifier against Iraq.
Some online reports suggested he'd been hauled off by coach Alberto Zaccheroni after a poor performance and others mischievously claimed he had broken his leg.
The likely truth is that he was wisely being rested for the more important game ahead. Nevertheless, when asked afterwards if 45 minutes was too short for him, Kagawa replied: "You can say that.
"I wanted to play longer. I always want to score but the coach makes the decisions.
"We all found it tough because of the hot weather, which should be good preparation for our next match.
"I don't know what kind of tactics Iraq will employ but I want to play well with my team-mates and score a goal."