Joachim Low, Germany's national coach, is to contact Chelsea next week to ask them to explain Michael Ballack's exclusion from their Champions League squad.

The Germany captain is recovering from ankle surgery and does not figure in his club's 23-man squad for the group stages of the competition.

Chelsea insist they took the decision because they could not guarantee Ballack would be fit for the majority of their six group matches. However, Low is confident of having the midfielder back for his side's European Championship qualifiers next month.

"For us, Chelsea's decision is unfounded," Low said. "At the moment, nobody can quite understand it."