Cesc Fabregas-Diego Costa
Chelsea duo Cesc Fabregas and Diego Costa may miss the game against Manchester CityGetty

Chelsea manager Jose Mourinho may have to face the crucial Premier League game against Manchester City on Saturday 31 January without key stars Diego Costa and Cesc Fabregas.

Spain international striker Costa was charged by the FA with violent conduct for an alleged stamp on Emre Can during the League Cup semi-final second-leg victory over Liverpool on Tuesday 27 January.

The former Atletico Madrid forward has until 6pm on 29 January to respond to the charge but if found guilty, he faces a minimum three-game ban, meaning he will miss the visit of Chelsea's title rivals as well the Premier League games against Aston Villa and Everton.

Meanwhile, Fabregas is a doubt after the Catalan midfielder was forced to leave the ground earlier in the game against Liverpool after suffering a hamstring injury.

Speaking after the game, Chelsea manager Jose Mourinho said he replaced Fabregas with Ramires as a precaution but the Spaniard is still expected to undergo a tests to see whether he will be available for the game.

"Fabregas was his hamstring. Cesc told me he wasn't yet injured but he would be in a few minutes, so it was more of a precaution," Mourinho said after the game.

The Blues host City in a potential title decider, with Chelsea five points ahead of Manuel Pellegrini's side at the top of the Premier League table. However, the loss of two key players could be a real blow for Mourinho.

Costa and Fabregas have been crucial for Chelsea during the first part of the campaign following their moves from Atletico Madrid and Barcelona respectively.

The striker has started 19 Premier League games scoring 17 goals, while Fabregas has only missed one league game due to suspension, providing 15 assist in his 21 league appearances.

Should the Spaniards miss the game, Didier Drogba or Loic Remy will be expected to cover Costa up front, while Ramires or John Obi Mikel could replace the midfielder.

Meanwhile, Branislav Ivanovic also finished the game against Liverpool with an injury but Mourinho suggested he was fine, while Filipe Luis is doubtful with a calf problem.

"Branislav could finish the game, Filipe Luis couldn't. At this moment I don't know [if they will be OK for Saturday]. Filipe was a calf problem," Mourinho said.

But even if Luis is fit, the Chelsea manager may opt to use Cesar Azpilicueta instead, as the Spaniard has been his first-choice left-back since the start of the season.