I reckon Arteta's going to start with:
------------Raya
White-Saliba-Gabriel-MLS
--------Zubimendi
-----Odegaard-Merino
--Martinelli-Gyökeres-Eze
Then bring on Saka and move Martinelli central. Or bring on Rice and move Merino up front.
Edit: Having just written all that down, I understand that the chances of him actually not starting Saka are quite slim. Especially after taking him off against Newcastle.