Japan captain Makoto Hasebe has had a second operation on his right knee, the midfielder announced Saturday on his blog.
Hasebe hurt the lateral meniscus in January during training with his German Bundesliga club Nuremberg, and had surgery on the knee the same month in Japan. He had resumed practice in Germany, but decided to return to Japan for a detailed examination, skipping a scheduled practice on Wednesday after complaining of discomfort in the surgically repaired knee.
The injury puts Hasebe's availability for June's World Cup in doubt.
"We have heard it may be possible for him to remain in Japan for a while," Japan Football Association technical director Hiromi Hara said. "We will discuss with the national team coaching and training staff and want to make a combined effort toward his rehabilitation."