Sami Khedira says his comeback is on track after playing the first half of Germany's shock defeat to Slovakia on Sunday.
Ahead of Euro 2016, however, the former Real Madrid midfielder is optimistic over his physical condition.
"My fitness is good," he said. "But the calf is always dangerous - you have to be careful.
"Overall, however, everything is on schedule."
Khedira departed against Slovakia with the score sitting at 2-1 to the visitors, who eventually ran out 3-1 winners, but he blamed the adjustment to a new formation for Germany's defensive issues.
Head coach Joachim Low trialled a three-man defence and Khedira insisted: "We have not done well due to the formation.
"We knew that there might be some co-ordination problems."
Germany now face Hungary on Saturday, before kicking off their Euro 2016 campaign against Ukraine the following weekend.