The 30-year-old skippered Germany to the World Cup semi-finals before arriving at Chelsea where he has played in the league and Champions League.
"I'm not running on reserve just yet but I have reached my limit in terms of the physical demands," he told Frankfurter Allgemeine Zeitung.
"We will see what it is like in spring not to have a winter break."
The midfielder, who agreed to join the Blues from European giants Bayern Munich prior to the World Cup, said he was pleased to have made the move to London.
"I deliberately gave up the nice footballing life that you have in Munich, as I wanted to prove myself and impose myself again," he added.
"Everything is quite new: the surroundings, the team, the level of expectation. At Chelsea all the players are of a high quality.
"The respected and privileged position that I carved for myself in Germany is no longer there. Good performances are crucial. But I'm happy that I took that step."
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So the German captain admits keeping his place in the side is so much harder, given the quality of players throughout the squad.
Regarding the physical tiring problem (which happens to almost every player without exception in the Prem season), I think the FA do seriously need to consider putting some sort of break in soon (this could be the time when England play 1 or 2 of their pointless friendlies), to give players like Ballack have a decent rest (especially in international tournament year).