Chelsea midfielder Michael Ballack admits he is beginning to feel the effects of the club's hectic Premiership schedule.
The 30-year-old captained Germany to the semi-finals of the World Cup last summer before making his debut for the champions shortly afterwards.
Ballack's recent form in the heart of the Chelsea midfield has been impressive as Jose Mourinho's side have kept the pressure on Manchester United at the top of the table.
The Germany international is beginning to show he can fit into a midfield which already contained England's Frank Lampard and Michael Essien.
However, with Chelsea's hectic fixture build-up, Ballack has sounded a note of caution and hinted he would not be averse to being rested during the winger period.
Ballack said: 'I'm not running on reserve just yet but I have reached my limit in terms of the physical demands.
'We will see what it is like in spring not to have a winter break,' he told Frankfurter Allgemeine Zeitung.
Ballack is set to make his 75th appearance for Germany in their Euro 2008 qualifier against Cyprus on Wednesday, and admits he gave up a nice life at Bayern Munich to try and prove himself at Stamford Bridge.
Ballack added: 'I deliberately gave up the nice footballing life that you have in Munich, as I wanted to prove myself and impose myself again.
'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.'
Meanwhile Chelsea are expected announce the signing of goalkeeper Magnus Hedman as cover for Carlo Cudicini and Henrique Hilario and the injured Petr Cech.
Chelsea will hand the former Coventry goalkeeper a contract until the end of the season and the goalkeeper flew back into London on Monday night to continue training with Mourinho's squad.
The 33-year-old is delighted to get the opportunity, and has already set his sights on getting an extended deal after the season is over.
Hedman said: 'The whole challenge is terrific. It's a fairytale from the beginning to the end, but that thought and feeling, I have to put behind me.
'It is serious now. The goal is to extend it beyond seven months. But my first job is to regain fitness. After all, it's 18 months since I last played,' told Expressen.