Midfielder Mateo Kovacic has returned to Chelsea training after missing the last eight games with a hamstring injury.
The Croatian pulled up with the issue during a training session in October and has not been seen since, with his absence coinciding with problems for fellow midfielders N'Golo Kante and Jorginho as well.
Kante has been sidelined with a knee injury and is facing an undetermined spell out, while Jorginho has been nursing a hip injury which has limited his involvement.
Numbers have been slim in Thomas Tuchel's midfield, but fortunately, The Times state that Kovacic is now back in training and is expected to be available for selection for Saturday's meeting with Leeds United.
Tuchel will, however, have to make do without Kovacic for Wednesday's trip to Zenit, with the 27-year-old still building up his match fitness. Ruben Loftus-Cheek or Saul Niguez will likely line up alongside Jorginho if the Italian is healthy.
A general fitness update on the team was given by football.london, who revealed that Tuchel could call upon Kai Havertz for Wednesday's game. The German limped off in the 3-2 defeat to West Ham but scans have shown that his injury is nowhere near as serious as first feared.
Havertz may well travel to Zenit, although he could be left out of the starting lineup if he is not completely ready.
Another player who was forced off against West Ham was Marcos Alonso, whose current fitness remains a mystery.
No update has been given on the left-back, who complained of pain in his back, but with fellow defender Ben Chilwell sidelined with his own problem, Chelsea fans will be keen to see Alonso return soon.
Tuchel has hinted at using Saul as a left-back, having seen the Spaniard play there during his time at Atletico Madrid, while it would not be a surprise to see Callum Hudson-Odoi deployed there as emergency cover.