Rafael Benitez has warned John Terry a place in his first XI is not guaranteed after the Chelsea captain's recent fitness troubles.
The 32-year-old has started twice for the Blues under Benitez, who was appointed interim boss in November, and was an unused substitute in last night's 1-0 Europa League last-32 first-leg win at Sparta Prague despite being available following a knee injury.
Branislav Ivanovic and Gary Cahill played in central defence as last season's Champions League winners recorded back-to-back wins for the first time since December and kept a clean sheet for a second time in eight games.
"He (Terry) had a setback," Benitez said. "After he was fine again. He had no reaction in the next training session.
"It's a vicious circle: if he cannot play, he cannot improve his match fitness. We have to manage.
"In the meantime if Cahill and Ivanovic are doing well at least we can keep winning games."
"It's a vicious circle: if he cannot play, he cannot improve his match fitness" - Rafael Benitez
Terry may yet return for Sunday's FA Cup fourth-round replay with Brentford.
Fernando Torres' most recent goal came in the drawn original tie with the npower League One club.
The £50million striker now has one goal in 13 games after missing a number of chances against Sparta, his evening summed up by a sliced second-half shot which went out for a throw-in in another impotent display at the Generali Arena.
Benitez, who managed Torres at Liverpool, refused to criticise his compatriot, even though the World Cup winner missed a straightforward attempt after 35 minutes, did not make an effort to meet two early crosses from Eden Hazard and looked disinterested at times.
"We have to create more opportunities and the strikers will score more goals," Benitez said.
"His work rate was really good and thanks to him the rest of the team, especially the second line of offensive players, they could create.
"Everybody expects from a striker just to score goals, but he's doing also a great job for the team."
Nevertheless Benitez called for Chelsea to be more clinical after Oscar came off the bench to score the winner eight minutes from time to claim the lead ahead of next week's second leg at Stamford Bridge.
"Eighteen attempts away is not bad, but we have to be more clinical in attack," Benitez said.
"We have scored the away goal and we have to finish the job at home."
Like Terry, Ashley Cole was an unused substitute, due to a cold and Benitez's wish to give Ryan Bertrand an opportunity.
Reinforcements are available for the Brentford clash.
Demba Ba, ineligible in the Europa League after playing for Newcastle earlier in the competition, David Luiz, suspended against Sparta, and Nigeria duo Victor Moses and John Obi Mikel could feature.
"We have more bodies and hopefully we can manage in a better way," Benitez said.