Ballack undermined by Chelsea row

The dispute between Chelsea and the German football federation (DFB) over Michael Ballack took a new twist yesterday when both sides blamed each other for the injured player missing a film-shoot in Cologne yesterday. Ballack returned to London on Sunday night understood to be deeply frustrated at his treatment from his club.

The saga, which was described by the Germany general team manager Oliver Bierhoff as "astonishing" came to a head on Sunday night. Ballack had been in Germany since Thursday and was scheduled to take part in a high-profile commercial shoot with Adidas and the DFB yesterday. However, he flew back on Sunday after, the DFB claimed, Chelsea failed to respond to requests to give him permission to stay.

The result has been that Ballack, 30, who has now not played in five months after two operations on an injured left ankle, is understood to be deeply disillusioned with his treatment by Chelsea. Controversially left out of the club's Champions League squad this month he is feeling more marginalised than ever.

The latest dispute has turned into a bizarre exchange involving, the DFB claim, a sequence of unanswered emails, letters and phonecalls that they sent and made to Chelsea over the last four weeks trying to gain permission for Ballack to stay in Germany to take part in the shoot. Eventually, when they went unanswered, Ballack was forced to return to London on Sunday night – much to the disappointment of Adidas, who have an eight-year, £100m deal with Chelsea.

When finally permission was granted by the club yesterday – when chief executive Peter Kenyon returned from a holiday in Cyprus – Ballack refused to return to Germany on principle. In Germany, the dispute has strained the relationship between the DFB and Adidas – who wanted to shoot their Euro 2008 German national team commercial – and Chelsea to breaking point.

Talking yesterday about the treatment of Ballack, Bierhoff said: "That's no way to deal with a German international, especially the captain of the team who is highly respected. And it's out of order to deal with Adidas that way."

However, sources at Chelsea have indicated that the DFB failed to make the correct approaches to them to obtain the special insurance clearance needed for Ballack to take part in the commercial. They say that the first letter they received from Bierhoff requesting permission was dated 31 August. Kenyon and his assistant have been out of the office since that date and Chelsea claim a follow-up phone call was made to the wrong department.

The details are likely to be disputed between both sides but what is undeniable is a growing uncertainty around Ballack's position at Chelsea.