Chelsea will be without midfielder Frank Lampard against Manchester City on Saturday.
The midfielder is understood to need more time to recover from his recent hernia surgery and so will miss the trip to Eastlands along with striker Salomon Kalou and midfielders Yossi Benayoun and Gael Kakuta.
Kakuta (back), Kalou (thigh) and Benayoun (calf) were all injured during Chelsea's 4-3 Carling Cup exit at the hands of Newcastle on Wednesday night. But Lampard is the biggest blow as the England midfielder was expected back in time for their first real test of the season against Roberto Mancini's side.
However, Chelsea midfielder John Obi Mikel hopes the Blues will continue their unbeaten run in the Barclays Premier League against City.
Chelsea have secured five straight league wins over West Brom, Wigan, Stoke, West Ham and Blackpool but City will present them with a different type of challenge.
He said: "If I was a defender playing against Chelsea, I would be very scared because you don't know where we're going to come from - we have Ashley Cole bombing forward on the left side all the time.
"So it is hard to know what to expect when we have all these players bombing forward all the time.
"If you look at our front three, none of them have a static position, they are all moving around.
"It is the same with the midfield although I tend to stay a little bit more because I cannot afford to leave that position.
"Playing that way helps us a lot while the other team is thinking about whether to follow Nicolas Anelka's runs, Frank Lampard or Michael Essien."