Germany boss Joachim Low is to contact Chelsea next week to ask them to explain Michael Ballack's exclusion from their Champions League squad.
The Germany captain is currently recovering from ankle surgery and does not figure in his club's 23-man party 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, suggesting he will not return until the end of October at the earliest.
However, Low is confident of having his influential midfielder back for his side's European Championship qualifiers next month and cannot understand why the English club are less optimistic in their assessment of his fitness.
'For us, Chelsea's decision is unfounded,' said Low.
'After the internationals, I will call Chelsea because it would certainly be interesting to find out why Jose Mourinho has made such a decision.
'At the moment, nobody can quite understand it.'
According to Sport Bild magazine, Ballack was in Munich yesterday undergoing further tests to clarify the extent of his injury with Germany and Bayern Munich team doctor Hans-Wilhelm Muller-Wohlfahrt.
It appears it is not only Low who finds the whole injury situation puzzling. The player himself is caught between pillar and post, according to the Germany coach.
Low said: 'Michael cannot quite explain for himself why Chelsea have not nominated him for the Champions League.'
Ballack's Champions League omission has fuelled speculation he will be sold when the transfer window re-opens in January but yesterday saw Chelsea rubbish such suggestions.
Bayern president Franz Beckenbauer has ruled out Ballack returning to the Bavarians in the winter, although Serie A leaders Juventus are a different option.
According to reports in Italy, the Bianconeri are considering making an offer in January, based on the recommendation of their former Bayern midfielder Hasan Salihamidzic.