Courtois has been number one at Stamford Bridge this term following his return from a number of loan spells at Atletico Madrid, with Cech losing his place between the sticks.
The Czech has made only one substitute appearance in the Premier League due to Courtois' form, but will now have the chance to impress.
Manager Jose Mourinho confirmed the injury to Courtois at his pre-match news conference on Friday and played down talk of Cech leaving the club.
"[Courtois] had a problem in training, a muscular problem and will not be available tomorrow," said Mourinho.
"[It is] a chance for Petr and a chance for Mark [Schwarzer] to be on the bench.
"We played Petr in three Champions League games and every League Cup game so we know what we have.
"I don't think it's possible [that he will leave]. I read a couple of weeks ago that his agent said there is no chance of him leaving in January.
"That, plus the fact I have no info on any offer to him, makes me believe 100 per cent that he will stay.
"I am so happy that we have this fantastic situation with the goalkeepers."
