#5. William Gallas
William Gallas took it too far in 2006 when he refused to travel with Chelsea on their pre-season tour to the United States. An angry Mourinho had said that he was terribly upset and that Gallas showed a lack of respect to the Chelsea family.
Gallas had made his intention of leaving clear when he did not sign Chelsea a new contract with the club. However, Jose took his revenge for the ‘lack of respect to the club’ by handing new signing Michael Ballack the number 13 shirt which belonged to Gallas, making it imminent that Gallas would be shown the door soon.
However, after Gallas’s transfer to Arsenal, there was a parting shot from Jose which perhaps was the only time that Jose did not personally attack Gallas but through the club. A statement released by the club reeked of Jose and his displeasure with the French defender was clear. The statement began with: “Chelsea believes it is important for our supporters to be made aware of the full facts regarding William Gallas and the lack of respect he showed to the fans, the manager and the club.
"Despite leaving he continues to attack José Mourinho and this cannot be left unchallenged.”
There was also mention of the fact that Mourinho had faced several attacks from William which included the threat of scoring an own goal if he was forced to play for Chelsea.
Gallas went on to deny the own-goal threats and the tension with the Portuguese manager has subsided since. However, the bad blood which existed between them then is no denying.