Itakura was on loan from Manchester City at Schalke for the past season and he impressed for the German club.
The centre-back played a vital part in helping his team earn promotion back to the Bundesliga, playing every match in the league after he came to the club.
Itakura made 31 appearances in the league and scored four goals while also playing in a midfield role when his team required it.
Celtic are interested in the centre-back and want to bring him to Celtic Park ahead of next season, adding to their Japanese contingent.
They could be in for competition though as Eintracht Frankfurt are watching the player, according to Sky Deutschland.
The German side are coming off the high of winning the Europa League, defeating Rangers in the final, and may look to add Itakura to deepen their defence.
His loan club Schalke also want to make his signing permanent, and Itakura himself has revealed his willingness to stay at the club.
Schalke though are in no position to meet his asking price until they sell players.
