Rafa Benitez said it is too early to confirm whether John Terry will return to the side for the Capital One Cup semi-final second leg against Swansea City on Wednesday.
Terry, who was injured in the 1-1 draw with Liverpool on November 11, made his return to first-team action this month when he came on as a 79th-minute substitute in the 4-0 victory over Stoke. However, he has failed to make it off the bench in the two games that followed.
Speaking ahead of the trip to the Liberty Stadium, Benitez was coy about whether the defender would be restored to the starting line-up.
"He was training, he was doing well," he said. "As I said before, he lacks match fitness, but he's training well. Yesterday we had a hard training session and he was doing well. Today he was training again. He's in the squad and he is an option."
Benitez said Terry understood that Chelsea "have a plan" to manage his return and suggested the form and fitness of other defenders may determine whether the captain would be selected.
"Tomorrow you have a problem and everything will change," Benitez said. "There might be a problem with the centre-backs and he's number one; we might not have any problems and then we'll decide."
The Blues are looking to overturn a two-goal deficit at Swansea as they look to book their place at Wembley, and Benitez feels his players are capable.
"We have to score, we have to win," he said. "We have confidence we can do it. Obviously we are playing a good team, but if you remember the first leg, we had a lot of chances then we made two mistakes and they scored. Now, we have to manage the situation, but our games away have been quite good so we are confident we can do it."
Benitez also refused to be drawn on whether Chelsea would look to further reinforce the squad this month.
"Do you think really that if I have any information I will give you a name? No, because maybe it will cost more money," he said. "We are just concentrating on this game so I can't be thinking about any additions."