John Terry has given Chelsea a fresh injury scare to contend with as Frank Lampard also battles to prove his fitness for Monday's trip to Bolton.
The club had said Lampard should shake off a minor calf injury in time.
But manager Carlo Ancelotti admitted on Friday: "Lampard's having treatment. I don't know if he's available or not.
"John Terry also had a little problem with his back. We have three days to check them. We have more possibility with Terry."
The Blues captain, who has spent spells on the sidelines with leg muscle and hamstring injuries this season, played 90 minutes in the 2-0 win against Blackburn last Saturday.
England midfielder Lampard went for a scan after picking up a knock in training on Thursday, but Chelsea described it as a "minor problem".
"Frank is expected to be available for Monday's match," the Blues said in a statement on the club website.
The 32-year-old returned to the side in mid-December after being sidelined since August with hernia and groin problems.
He has looked increasingly sharp and scored twice in the 7-0 demolition of Ipswich in the FA Cup third round.
His importance to Chelsea's midfield was underlined earlier this week after they missed out of signing Steven Pienaar from Everton, with the South African opting to join Tottenham instead.
The Stamford Bridge club are fourth in the Premier League, seven points behind leaders Manchester United, who have a game in hand.
Earlier this month, Lampard conceded his team have been lacking in confidence.
"You lose the feeling of being able to win every week," he said. "Once you've had that and lose it, it's hard to get it back."
