The Blues, who beat Servette 2-0 in last week's first leg, are set to be without captain Reece James as he continues to recover from a hamstring injury, so either Malo Gusto or Axel Disasi are expected to start at right-back.
Romeo Lavia sustained a hamstring problem before Chelsea's thumping 6-2 Premier League win at Wolverhampton Wanderers last Sunday and is a doubt for the clash with Servette, as is Moises Caicedo who was taken off midway through the second half against Wolves following a strong collision.
Meanwhile, Wesley Fofana, Ben Chilwell and Raheem Sterling are also unavailable for selection as they have all been omitted from Chelsea's Conference League squad.
Enzo Maresca made nine alterations for the win over Wolves from the side that beat Servette last week and the Italian is expected to ring the changes once again on Thursday, with goalkeeper Filip Jorgensen in line to replace Robert Sanchez between the sticks.
Tosin Adarabioyo and Benoit Badiashile were both handed starts at centre-back in the first leg and could be recalled to start on Thursday, while either Renato Veiga or Marc Cucurella are set to play at left-back.
Lavia and Caicedo both started the first leg, but as they are doubtful, Maresca could select Enzo Fernandez and Kiernan Dewsbury-Hall in centre-midfield, while a decision will be made on whether to name star playmaker Cole Palmer in the first XI or have the 22-year-old begin as a substitute.
Noni Madueke scored a superb 14-minute hat-trick against Wolves, with all three goals assisted by Palmer, and he could retain his place on the right flank, while Pedro Neto, Mykhaylo Mudryk and Christopher Nkunku all battle for a start on the left.
Nkunku is also an option to play as a number 10 instead of Palmer, as is new signing Joao Felix who was not available for the first leg, and both players could also do a job up front if Maresca opts against selecting either Nicolas Jackson or Marc Guiu as his centre-forward.
Chelsea possible starting lineup: Jorgensen; Disasi, Tosin, Badiashile, Cucurella; Fernandez, Dewsbury-Hall; Madueke, Felix, Neto; Nkunku