Khedira, 31, part of Germany's 2014 World Cup winner, was among a number of players sharply criticised for their performances in Russia in June after Germany crashed out of the World Cup in the group stage.
It was Germany's earliest exit at a World Cup in 80 years, putting the national team future of several players, including Khedira, in doubt.
"After a good season and nine goals with Juventus, I played my two worst matches at the World Cup with full fitness. That was really bad," Khedira, who plays for Italian club Juventus, said on his Instagram account.
Germany finished last in their group with just one win - over Sweden - and defeats to Mexico and South Korea. Khedira played in both those defeats, having been dropped against Sweden.
"The criticism against me and us all is justified," he said, while adding he was ready to fight for his spot on the team.
"It must be an honour for any active player to play for this country, this (DFB) association and this team," said Khedira.
"If there are better players at the moment then I will accept it. But should I be nominated because the coach believes I can help the DFB then for me it is always an honour and an obligation."
Fellow midfielder Toni Kroos has also said he wants to continue with the team, while Mesut Ozil announced his international retirement in July, saying he had faced "racism and disrespect" because of his Turkish roots after he appeared in a photo with Turkish President Tayyip Erdogan.
(Reporting by Karolos Grohmann; Editing by Mark Heinrich)
