Itakura will go under the knife on Friday because of a nagging ankle injury and looks unlikely to be fit for country's World Cup second round qualifiers on November 16th against Myanmar and against Syria five days later.
Itakura had played in Japan's most recent game, a 2-0 win over Tunisia on October 17th.
"He will not be available for the club for the next few weeks," Gladbach said in a statement.
The Foals are in 13th place in the Bundesliga on six points from eight matches.