Chelsea will hope Juan Mata can play through the pain after sustaining a suspected broken finger in the 3-1 defeat by Napoli.
The Spaniard, who was involved in a first-half collision with Salvatore Aronica shortly after scoring his club's goal, is set to undergo tests to ascertain the extent of the injury.
Mata's absence would be the last thing Chelsea need amid what has become a crisis following a five-game winless run.
Manager Andre Villas-Boas is under severe pressure and he will be hopeful one of his best players is fit for Saturday's Premier League home game against Bolton.
Mata said regarding his finger: "We have to check it. Maybe it is broken."
The loss in Italy has left Chelsea's Champions League hopes hanging by a thread, while Villas-Boas' job prospects are looking increasingly bleak.
But Mata on Tuesday night said he was positive the Premier League club could turn the tie around in the second leg.
He told Sky Sports: "I have confidence in this team, we are not dead. It will not be easy for us but I think we can do it."
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