Mesut Ozil does not "identify" with the Germany national team and could retire from international football after the World Cup, former star Lothar Matthaus says.
Along with the rest of the world champions, Ozil was the subject of criticism after starting their World Cup campaign with a 1-0 defeat to Mexico.
"I often have the feeling that Ozil does not feel comfortable in the Germany jersey, that he is not free, almost as if he does not want to play at all," the 1990 World Cup winner wrote in Bild. "There is no heart, no joy, no passion.
"It does not seem impossible that he might withdraw from the national team after the World Cup.
"For a year or two, Ozil has been much weaker and at a level that does not justify the free ticket Low gives him."
Ozil and Ilkay Gundogan created a controversy before the tournament when they appeared in a picture alongside Turkey president Recep Tayyip Erdogan, and Matthaus believes the Arsenal star does not realise how provocative it was.
"Ozil did not understand why there are such great discussions in Germany about him. He is unaware of what the people in Germany expect from a national player, and that it would have been right, after the mistake of the Erdogan photo, to show commitment to Germany and to open up to the fans."
Matthaus continued his criticism of Germany in an article for Sky Sport, saying: "I don't care about Mesut Ozil's attitude towards the team and the fans or that he does not sing along with our national anthem. But I cannot understand why he does not consider it necessary to acknowledge the fans and clap briefly.
"If you have already made a mistake, then such a gesture would have been a beautiful symbol towards the national team, but I feel he does not identify with this one. He gives the impression that he is in his own world and not part of this team."
Matthaus did more than just hit out at Ozil after their disappointing start to the World Cup, saying they lacked all the strengths of a typical German team.
"[There was] no pressing, no stability. The distances were so big that you were almost scared," he added. "Especially the gaps between central defenders and midfielders. There should never be between 30 and 40 metres in between them. Our virtues were not there. Everything a German team has always been was non-existent.
"The so-called Low regulars have abandoned our national coach. By that I mean above all Ozil, Sami Khedira and Thomas Muller."