According to an NBC Sports source with 'inside knowledge', Fabregas and Hazard were "leading the charge" and it was the Spanish midfielder in particular who was the main protagonist, complaining to the Chelsea hierarchy about Mourinho.
Fabregas was accused of leading a dressing room revolt only last month, but strongly denied the claims made by the Secret Footballer - a retraction was later written and apology extended to the player.
Just this week, it was also reported that he was at the centre of a training ground brawl following a hard tackle on a member of Chelsea's Under-21 squad in a mixed session.
According to the Daily Mail, Roman Abramovich told the Chelsea players at training on Fri
It is said that he also made it clear that this should now be considered a fresh start and that immediate improvements are expected in terms of results over the coming weeks.
As yet it remains to be seen who will take over for the remainder of the season. Guus Hiddink is the clear favourite and has been in talks over returning to fill a similar role to the one he had for three months in 2009.
The veteran Dutchman is expected to be at Stamford Bridge on Saturday when Chelsea face Sunderland, although he has hinted that not everything is quite so clear cut just yet.
"I want to gain as much information as possible. Chelsea is in a bad situation and there are reasons for that. Before I take a decision, I want to have insight," he was quoted as saying on Friday.
"Whether or not I'm visiting their next match depends on my first conversation. Then I'll decide if I should stay in London longer."