The money
Abramovich handed Mourinho a new four-year contract in August, worth around pounds 10?million a year, so he would be due a healthy pay-off if sacked. Chelsea have learnt from the last time they dismissed Mourinho and had to pay about pounds 18?million. Since then sacked Blues managers have been given the option of a year's money up front, or being paid until they find another job. The bill for firing Mourinho would probably be around pounds 10?million and, while the current contracts of Guardiola and Conte may be running down, it would cost a further pounds 15?million to take Simeone from Atletico.
Special One
Mourinho may be struggling badly now, but he is the most successful manager in the club's history. Sacking him for a second time would be a permanent farewell and Abramovich is wary of making the final cut too soon. The Russian publicly backed Mourinho early in the season, but put all the pressure on the Portuguese by making it clear results had to improve with the current squad of players. Mourinho will not be short of clubs willing to give him his next job if he leaves Chelsea, and could even return to Real Madrid.
The short term
Perhaps the most difficult question facing Abramovich is who he would replace Mourinho with if he sacks him during the season. The two most experienced available managers, Carlo Ancelotti and Guus Hiddink, are both well known to Abramovich. Having been sacked just a season after winning the Double at Chelsea, Ancelotti would surely not want to return as a caretaker, while Hiddink's reputation took a battering during his last job in charge of the Holland national team. Abramovich is also short of internal candidates, as most of Mourinho's staff travel around with him.
The long term
Pep Guardiola has long been the dream for Abramovich. Independent intermediaries have been working on trying to set up a deal for Guardiola to take over next summer, but Bayern Munich want to keep the Spaniard and Manchester City are also interested. Guardiola has turned Abramovich down once in the past. Diego Simeone has achieved great success at Atletico Madrid but does not speak a word of English. Antonio Conte's Italy contract expires after Euro 2016, while the CSKA Moscow and Russia coach, Leonid Slutsky, could be a contender.
The fans
Roman Abramovich found himself accused of ignoring the fans when he sacked Roberto Di Matteo and made unpopular Spaniard Rafael Benitez interim manager. Supporters applauded in the 16th minute of games in honour of Di Matteo, who wore the No?16 on his shirt during his playing days, and made it clear they did not want former Liverpool manager Benitez. Despite pressure mounting on Jose Mourinho, he still has the fans onside. They sang his name even when Chelsea were losing at home to Liverpool and the majority would be upset by his exit.