The Belgium striker has come under scrutiny for his performances of late, highlighted by a particularly underwhelming display against Crystal Palace.
Lukaku managed just seven touches in the Premier League clash, a record low for a 90-minute Premier League appearance since Opta began collecting such data in 2003.
Having joined from Inter Milan for around £97million, Lukaku's impact has not been what Chelsea would have wished.
Kai Havertz will likely lead the line in Lukaku's absence.
Chelsea: Mendy, Christensen, Thiago Silva, Rudiger, Azpilicueta, Kante, Kovacic, Alonso, Ziyech, Havertz, Pulisic. Subs: Arrizabalaga, Jorginho, Lukaku, Werner, Loftus-Cheek, Bettinelli, Chalobah, Saul, Mount, Kenedy, Sarr, Vale.
Lille: Leo Jardim, Celik, Fonte, Botman, Djalo, Onana, Xeka, Andre, Sanches, David, Bamba. Subs: Grbic, Gudmundsson, Ben Arfa, Yilmaz, Lihadji, Gomes, Weah, Zhegrova, Bradaric, Raux.
Former Chelsea striker Tony Cascarino also gave his verdict on Lukaku being left out of the Blues team.
He told talkSPORT: "He's also a Belgium international and their top scorer ever. He's come to Chelsea and everyone's expected him to be like Didier Drogba and score big goals in big games.
"He's probably speaking to whoever his agent is and saying 'what's the process now?'
"It's hard to process what Romelu Lukaku is going through.
"Is it too soon to stay Lukaku is over at Stamford Bridge?"