The 31-year-old, who has scored 48 times in 95 games for his country, struggled for games and goals with Bayern Munich last season. And he looked a shadow of the player who finished top scorer at the 2006 FIFA World Cup in Saturday night's friendly win over Hungary in Budapest.
"It is clear that it will be no easy task to get Miro in form," Low said in the Bild newspaper. "It will be hard work, for him, for us. He has to work a lot. He still hasn't shown the form that he is actually capable of. For Miro it is now about becoming more certain in training."
Low, though, offered words of encouragement for Klose, who has scored five goals in each of the last two FIFA World Cups. "People have often written Miro off before," he added. "But when it comes to it, he is there."
Klose's last international goal came in the 1-0 FIFA World Cup qualifying win away to Russia last October.