According to Krone.at, Leon Klassen stated that his sporting situation at Darmstadt was not what he had expected or hoped for, which is why he moved on loan to GAK for the spring. Klassen said he wants to further his development at GAK and that it is extremely important for him to play.

Grazer AK, a club in the Austrian Bundesliga, has signed 25-year-old former Spartak Moscow defender Leon Klassen on loan from the German club Darmstadt. The Austrian team confirmed the transfer of the former Russian youth international. Tino Vavra, the sporting director for Grazer AK, stated that Klassen is a technically gifted player who is an excellent fit for the team's style. Vavra also mentioned that Klassen will bring valuable experience gained abroad, including in Austria, and that he was convincing during their negotiations, expressing confidence that the player will make the team more flexible on the flanks. Klassen made 5 appearances in the 2. Bundesliga in the first half of the season and has a current market value of €600k, according to Transfermarkt.