Interim Chelsea manager Rafael Benitez has confirmed Petr Cech and David Luiz will miss the clash against Reading on Wednesday.
Benitez also bemoaned the number of games his side have had to play over recent weeks and believes his squad lack strength in depth.
Their depth will be tested at Madejski Stadium, with Cech and Luiz both missing through injury.
Benitez told reporters: “We are playing more games than anyone. In some positions we have only two or three players, that’s the reality.
“After the Africa Cup of Nations, and when we get Eden Hazard back, we’ll be able to manage a bit better.
“I’m really focused on my job. We know we are training well and preparing properly, and that’s my job.”
Chelsea avoided an early exit from the FA Cup on Sunday after grabbing a late equaliser in their 2-2 draw against Brentford, with Fernando Torres ending an eight-game goal drought.
Benitez, whose side sit third in the English Premier League, was keen to take positives from that match.
“The positive is that we are still scoring goals and conceding less than in the past, but we still need to improve,” he said.
“I was really pleased with John Terry against Brentford after not playing for such a long time.
“My focus is to improve the team and keep the players believing that we can win. I like managing top sides and this is one.”
Chelsea travel to face an in-form Reading side on Wednesday as they look to remain in the Premier League title race, but Benitez is aware his side face a tricky test.
“Reading will be a tough game, we know they play with high intensity and we have to be ready,” he said.