The president of the German Football Association has expressed his doubts after Michael Ballack apologised to Joachim Low.
Ballack recently fell out with Low after declaring in a German newspaper that he had been disrespectful to senior players.
The Chelsea midfielder issued a statement over the weekend saying he was sorry for his remarks, and promised to apologise in person as soon as possible.
However, DFB chief Theo Zwanziger fears Ballack's actions could be just a ploy to avoid being stripped of the captaincy.
"The apology has taken the edge off the conflict. And at least it has now been clarified that the mistake clearly lay with our captain," Zwanziger told Die Welt.
"Now we certainly have to face the question: How reasonable is Michael Ballack? Is the apology only tactics or is it really meant honestly?"
Ballack is currently recovering from a foot injury and has not been allowed by Chelsea to travel to Germany to meet up with Low.
The Germany coach has insisted that he will not fly to London to see Ballack for clear-the-air talks.