The 28-year-old World Cup finalist had already angered the club by failing to return on time for their tour of the United States which stirred the flames as he has said he wants to leave because he is not playing in his favoured central defence role and instead at full-back.

He has a year left on his present contract but talks had been going on prior to the World Cup finals about a new four-year one -- however the stylish former Marseille star has no end of suitors including Italian giants AC Milan.

However Chelsea's actions in handing Ballack the number 13 shirt looks to have provoked an irreparable rift, especially as the German captain, signed on a free transfer from Bayern Munich, had been told he would be wearing number 19.

"It is not possible for them to give Ballack the number 13 shirt without talking to William first," Gallas' agent Pierre Frelot told the BBC.

"William has been wearing that shirt for five years and it is the shirt he expects to be in.

"As far as we are concerned William's absence (from training) is still a misunderstanding.

"I am surprised they haven't waited to hear the explanation of the player in person first before releasing a statement and taking action against him."

Gallas has played more than 200 times for Chelsea since joining from Marseille five years ago for six million pounds and has been a pivotal part of their two title winning sides.

Gallas had requested extra-time off following the World Cup but was informed he should still report to Los Angeles on the date previously agreed.

His failure to report had club officials on Tuesday considering further disciplinary action as a consequence.

"William Gallas will not be joining up with Chelsea on the pre-season tour of the United States," read a statement from the club on Tuesday.

"William requested extra-time off following the World Cup but was informed he should still report to Los Angeles on the date previously agreed with him. He did not report and further action will now be considered by the club as a consequence.

"Pre-season training and the tour is about building team spirit among our squad and extra leave is only granted for valid football-related reasons."

Chelsea boss Jose Mourinho insisted however that Gallas for now at any rate was still in the picture.

"Obviously I'm disappointed but he is still in the team. He will start training Friday in England."