Chelsea manager Jose Mourinho has accused rebel William Gallas of showing him and his team-mates a lack of respect.

The France defender, who has just a year left on his contract, did not report for training in the United States as the Premiership champions prepare for the new season.

Gallas claims he is tired after his World Cup exertions, with France reaching the final before losing on penalties to Italy. Chelsea have threatened to take action against the player despite insisting that both parties were still talking over a new deal.

He has gone on record stating a desire to move abroad and his days appear to be numbered at Stamford Bridge with Michael Ballack revealing he had eventually been handed his lucky number 13 shirt, having initially been told that Gallas would keep his number.

Mourinho said: "It's not only me that is upset - we're all upset. Everybody is upset because we had a strong family and a strong group and this has shown a lack of respect to everybody and I don't like that."

But Mourinho has tipped summer signing Mikel John Obi to be one of the world's greatest players in two years. The Nigeria international has finally joined up with the Blues after their feud with Manchester United and Lyn Oslo was resolved following an amazing transfer wrangle.

Chelsea will pay their English rivals £12million and the Norwegian club £4million despite not playing for the Old Trafford club, who he initially signed for before indicating his desire to move to Chelsea.

But now that long-running saga is behind him, he has joined up with his new team-mates. Mourinho likes what he has seen and he is convinced if he can keep his feet on the ground the player will succeed at the top level.

"Mikel John Obi is Mikel John Obi," enthused the Portuguese boss, who put a fatherly arm around the player. "I hope the brain helps and I believe the brain will help him in the next couple of years become one of the best players in the world.

"I hope the brain, the personality, the character can help because his football is amazing. He has had very little football but he has been here for the last two days and you can see the qualities he has. We cannot make mistakes in the judgement so I just wish him a lot of success at Chelsea.

"I just hope he and the people around him can help him to be a good personality because he has the ability to be a real star."