The £50million summer signing was due to start at the Emirates, but is the latest member of Mikel Arteta’s squad to contract Covid-19 after four players caught it last week.
It means Mikel Arteta has to go with a back four, with Pablo Mari being drafted in along Rob Holding, with Bukayo Saka taking a more advanced role on the left in front of Kieran Tierney.
The Gunners struggled with a back-four against Brentford last week and they have previously had success playing a back-three against the Blues.
Gunners captain Pierre-Emerick Aubameyang was in the same boat last week after catching Covid-19, and is back among the substitutes here.
New signing Martin Odegaard is unavailable for the game with Chelsea as he is awaiting visa clearance following his move from Real Madrid, though fellow new arrival Aaron Ramsdale is on the bench.
Gabriel (knee) Nketiah (ankle) and Partey (ankle) are still not fit.
Confirmed team news
Arsenal XI: Leno, Cedric, Holding, Pablo Mari, Tierney, Sambi Lokonga, Xhaka, Saka, Smith-Rowe, Martinelli, Pepe
Subs: Aubameyang, Maitland-Niles, Tavares, Chambers, Nelson, Elneny, Balogun, Kolasinac, Ramsdale
Chelsea XI: Mendy, Azpilicueta, Christensen, Rudiger, James, Jorginho, Kovacic, Alonso, Mount, Havertz, Lukaku
Subs: Arrizabalaga, Thiago Silva, Kante, Werner, Chalobah, Zouma, Hudson-Odoi, Chilwell, Ziyech
Sunday 4.30pm GMT, Sky Sports
Venue: Emirates Stadium
Referee: Paul Tierney
Injured: Gabriel (knee), Lacazette (Covid-19), Nketiah (ankle), Partey (ankle), Runarsson (Covid-19), Willian (Covid-19), White (Covid-19)