It had been hoped that one or potentially even both summer signings could possibly be on the bench at last after injury, but neither have made it this afternoon. Captain Reece James and Marc Cucurella are both suspended, meanwhile.
Summer signing Lavia has stepped up his recovery this week and taken part in a partial team training session for the first time.
Nkunku, who like Lavia has yet to make his debut, already reached that landmark last week, but Chelsea are treading cautiously in bringing back the duo to avoid aggravating their injuries.
"We need to assess tomorrow and then decide, they are close and tomorrow we will make a decision," Mauricio Pochettino said on Friday.
"Lavia is maybe more difficult, but we need to assess Christopher Nkunku tomorrow."
Ben Chilwell, Malo Gusto, Trevoh Chalobah, Wesley Fofana and Carney Chukwuemeka are out.
James was sent off for two yellow cards in the 4-1 defeat away at Newcastle last weekend. Cucurella also has a one-match suspension after picking up his fifth booking of the season.
Levi Colwill and Axel Disasi are drafted into defence to replace the banned duo, joining Thiago Silva and Benoit Badiashile despite their mistakes against Newcastle.
Moises Caicedo comes in against his former club in midfield and replaces Lesley Ugochukwu. Enzo Fernandez and Conor Gallagher join him.
The steady front three of Cole Palmer, Nicolas Jackson and Raheem Sterling is disrupted with Palmer on the bench amid reports of a minor injury, with Mykhailo Mudryk starting instead. Robert Sanchez is in goal as usual.
Brighton are facing a major injury crisis of their own for the visit to west London, most recently losing Ansu Fati and Tariq Lamptey, who joined an extensive absentee list.
Chelsea XI: Sanchez, Disasi, Thiago Silva, Badiashile, Colwill, Caicedo, Fernandez, Sterling, Gallagher, Mudryk, Jackson
Subs: Madueke, Broja, Palmer, Petrovic, Maatsen, Deivid Washington, Gilchrist, Bergstrom, Mato
Injured: Chukwuemeka, Chilwell, Chalobah, Fofana, Gusto, Nkunku, Lavia
Suspended: James, Cucurella
Time and date: 2pm BST on Sunday December 3, 2023
Location: Stamford Bridge