Chelsea defender Ashley Cole has suffered knee ligament damage - but skipper John Terry is expected to return from injury on Saturday.
Cole damaged his posterior cruciate ligament when landing awkwardly during the win over Blackburn on Wednesday.
But the club say he does not need surgery and the 26-year-old is expected to play again this season.
Terry, out since December, had surgery on a back injury and his rehabilitation was complicated by a calf injury.
But he is expected to play against Charlton, with manager Jose Mourinho saying: "Terry is an important player for us. We've missed him and it's important he's back, especially in a period when we keep losing players."
Cole had a scan on his injury on Thursday and it had been feared that he would be out for the rest of the campaign.
It is the latest in a line of injuries to key defenders at Chelsea, with Terry only just set to return after more than a month out and fellow centre-back Khalid Boulahrouz also injured.
Mourinho said: "We are doing so many things to have a team to compete in all competitions and we must compete without Ashley.
"Khalid Boulahrouz will train with the group for the first time on Thursday and maybe in one more week he can play."