Jose Mourinho has two games to save his Chelsea job, club sources have told ESPN FC, with Carlo Ancelotti interested in taking over even on a temporary basis.
Chelsea's dismal form has seen them suffer six defeats in 11 league games this season.
Although club owner Roman Abramovich has wanted to give Mourinho time, sources said his vote of confidence after the home defeat to Southampton in early October would only extend until the November international break.
If Chelsea struggle against Dynamo Kiev in the Champions League at Stamford Bridge on Wednesday and face a group stage exit, the trip to Stoke next Saturday could be decisive for Mourinho.
Abramovich wants to look at the two games, together with Saturday's 3-1 home defeat to Liverpool, before coming to any decision.
With no immediate sign of the situation being turned around, sources said the majority of the players were now questioning Mourinho.
The view within the club is that if Mourinho is sacked, the international break would give a replacement time and would be the optimum moment for a change.
Although Chelsea have not directly approached Ancelotti, contact has been made with intermediaries.
The Italian has told his representatives he is interested, even if that only means taking the job until the end of the season.
Ancelotti -- who was at Chelsea between 2009 and 2011, winning the Double -- has privately described the club as the most difficult he has managed but would be willing to come back.
Meanwhile, Mourinho admitted the importance of the Champions League clash with Kiev as he previewed the game on Chelsea TV.
"It's a big game. It's a game that we cannot lose," he said. "We still can finish first, second or third, and obviously we want to finish in the top two."
The Chelsea boss said he could not fault the efforts of his players in the defeat by Liverpool.
"There are things that are out of our hands. The players tried. You could feel, and not just because we scored in the first couple of minutes, the attitude, desire," he said. "It was 50-50 despite the fact we were winning 1-0.
"There were two minutes of added time [in the first half] and we conceded the goal after two minutes and 35 seconds.
"What happened in the second half was a consequence of crucial moments, moments that the stadium saw, and more than just see it, the players felt it.
"From then, what happened was just a consequence."
Mourinho said he was delighted that the Chelsea fans had sung his name in a show of support.
"I take comfort, but what feeds me is not just the support of the fans but also the recognition of our work -- and that is by getting results," he added.
"I have some players really sad in the dressing room, and I'm full of respect for them."