The Brazilian hurt his shin during the 4-1 Carabao Cup defeat to Manchester City on Tuesday, but the injury was not too serious.
The Brazilian keeps his place in attack, but Pierre-Emerick Aubameyang is also on the bench after recovering from a calf issue.
Granit Xhaka has finished his suspension so could return in midfield, with Dani Ceballos and Mohamed Elneny having started the last three games.
In defence, Rob Holding, Kieran Tierney and Pablo Mari make up a back three.
Arsenal XI: Leno, Holding, Pablo Mari, Tierney, Bellerin, Elneny, Xhaka, Saka, Smith-Rowe, Lacazette, Martinelli
Subs: Ceballos, Runarsson, Aubameyang, Maitland-Niles, Cedric, Pepe, Mustafi, Willock, Nketiah
Today 5.30pm GMT, Sky Sports Main Event/Premier League
Arsenal squad from: Leno, Macey, Runarsson; Bellerin, Cedric, Chambers, Gabriel, Holding, Luiz, Mustafi, Kolasinac, Mari, Tierney, Saliba; Ceballos, Elneny, Maitland-Niles, Saka, Smith Rowe, Willock, Xhaka; Aubameyang, Balogun, Lacazette, Martinelli, Nelson, Nketiah, Pepe and Willian.
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