The Blues are hoping for an improved campaign on the European front after being thoroughly outclassed by Bayern Munich at the last-16 stage in 2019-20.
However, after witnessing his side squander a two-goal advantage against Southampton in the Premier League at the weekend, Frank Lampard will continue to have concerns about his inconsistent backline.
Here, Sports Mole rounds up Chelsea's latest injury and suspension news ahead of the clash with last season's Europa League winners.
Type of injury: Knee
Possible return date: Unknown
Gilmour is continuing his recovery from knee surgery, and Lampard recently revealed that the midfielder was "progressing well". However, the Scottish youngster will not be back in contention until the back end of November at the earliest.
Status: Major doubt
Type of injury: Thigh
Possible return date: October 20 (vs. Sevilla)
Having sustained a thigh injury while on international duty with Senegal, Mendy was sidelined for Saturday's top-flight match. While the stopper is not far away from a return to action, it would come as a surprise if he was risked in midweek.
CHELSEA'S SUSPENSION LIST