Germany manager Oliver Bierhoff has accused Chelsea of denying Michael Ballack permission to participate in an adidas promotional campaign.
Chelsea denied the suggestion tonight but by then Bierhoff had already gone public in his condemnation of the London club.
'That is not how you treat a Germany player and in particular our captain,' said Bierhoff.
'He is regarded highly throughout Europe and I am astonished by the way Chelsea have acted.'
Bierhoff was puzzled by Chelsea's stance given the club also have a sponsorship deal with adidas.
'It is absolutely not right that they act like this with us and adidas, who are also their partners, but it seems they have different methods at their club,' added Bierhoff.
'We will certainly be going back to them to follow this up.
'Having direct contact and sharing our views is important and we will certainly be giving them our opinion.'
The Germany captain is currently recovering from ankle surgery, an injury which prompted Chelsea to leave him off their 23-man squad list for the group stage of the Champions League.
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.