The former Atletico Madrid man sustained an ankle injury during the Gunners' recent 2-1 defeat to Chelsea, and there are fears that he may be sidelined with the issue until September.
Arsenal may be counting their blessings that Roma did not fork out enough to sign Granit Xhaka given Partey's injury woes, and the Switzerland captain could now find himself alongside Mohamed Elneny in the middle.
Albert Sambi Lokonga will likely be kept in reserve for a North London derby - albeit a 'friendly' one - but fellow new arrival Ben White could be deemed ready for his first start in defence alongside Pablo Mari.
Kieran Tierney and Calum Chambers seem set to start the campaign as Arsenal's first choice full-backs as Hector Bellerin continues to be linked with a move to Inter Milan, while Bernd Leno remains Mikel Arteta's number one for now.
Bukayo Saka was pictured arriving back at London Colney to a wall of supportive messages, but the 19-year-old will not be ready to feature from the off just yet, so an unchanged attack of Alexandre Lacazette, Pierre-Emerick Aubameyang, Emile Smith Rowe and Nicolas Pepe could line up in North London.
Arsenal possible starting lineup: Leno; Chambers, White, Mari, Tierney; Xhaka, Elneny; Pepe, Smith Rowe, Aubameyang; Lacazette