Mourinho is under intense pressure after watching his reigning champions slip to their sixth defeat in 11 games as they were dumped out of the League Cup on penalties at the Potteries.
The loss comes just three days after the 2-1 defeat to London rivals West Ham United and piles the pressure on the Portuguese, despite being the club's most successful ever boss.
So spectacular is Chelsea's fall from grace this season, it has been rumoured he has lost the dressing room and could lose his job next.
But reporting for BBC Sport former Queens Park Rangers and West Ham star Sinclair has rubbished suggestions Blues players and fans are turning on Mourinho.
However, the pundit is less sure about the man who matters most, owner Roman Abramovich.
"The way the players put themselves about and competed, Chelsea have a lot of positives to take," Sinclair told BBC Sport.
"This won't be the game that breaks the camel's back but it's another loss.
"Jose Mourinho clapped the fans when he came off and they reciprocated.
"The fans are clearly behind him, we have to wait and see if the owner is."
Sinclair also praised the way Mourinho handled the defeat after speaking to the former Real Madrid boss afterwards.
"Jose Mourinho came across composed, entertaining, factual and even answered my question post match tonight," Sinclair posted on Twitter.
There is a real sense of deja vu about the situation at Chelsea this season.
It was eight years ago that signalled the beginning of the end of the self-styled 'Special One's' first spell as Chelsea manager.
After the Blues' group stage Champions League draw with minnows Rosenborg in 2007-08 Mourinho left Stamford Bridge by "mutual consent".
Back then, pressure had been mounting following a 2-0 loss at Aston Villa and a 0-0 draw with Blackburn Rovers in the Premier League.
The big difference that season was that Chelsea were still fifth in the table despite their indifferent start and only two points behind leaders Arsenal.
But this time around they are 15th spot in the table, a full 11 points behind leaders Manchester City more than a quarter of the way through the season.