Cech has been ruled out for up to three weeks with a groin injury.
The 30-year-old suffered the problem at Everton on Sunday.
It enabled back-up keeper Ross Turnbull to step in for Wednesday night's 1-0 home defeat by QPR in only his fifth Premier League game for the Blues.
In a club tweet, manager Rafa Benitez provided a medical update on Cech, saying: "Two or three weeks. We are quite optimistic."