Trossard is making his first league start for the Gunners since his January move from Brighton & Hove Albion, forcing Gabriel Martinelli down to the bench in the process.
The Belgian is one of two alterations to Mikel Arteta's first XI, as Takehiro Tomiayasu unsurprisingly makes way for Ben White after his disappointing night against Manchester City.
Meanwhile, Partey is once again left out due to a muscular concern, which allows Jorginho to make his second successive start in the engine room alongside Granit Xhaka.
Emile Smith Rowe has also recovered from a thigh niggle to force his way back into the squad, and Arteta has otherwise kept changes to a minimum despite the rapid turnaround.
Meanwhile, Aston Villa boss Unai Emery has made five changes to the side that lost to Man City last weekend, as Tyrone Mings returns to demote ex-Arsenal man Calum Chambers to the bench.
John McGinn, Alex Moreno, Matty Cash and Philippe Coutinho are also brought in from the first whistle, replacing Jacob Ramsey, Lucas Digne, Ashley Young and Leon Bailey respectively.
Arsenal starting lineup: Ramsdale; White, Saliba, Gabriel, Zinchenko; Xhaka, Jorginho; Saka, Odegaard, Trossard; Nketiah
Subs: Turner Tomiyasu, Holding, Kiwior, Tierney, Vieira, Smith Rowe, Nelson, Martinelli
Aston Villa starting lineup: Martinez; Cash, Konsa, Mings, Moreno; McGinn, Kamara, Luiz; Buendia, Watkins, Coutinho
Subs: Sinisalo, Young, Chambers, Digne, Dendoncker, Ramsey, Traore, Bailey, Duran