The Brazil international hurt his knee in the 2-2 draw with Liverpool last weekend and was nowhere to be seen for the 3-0 EFL Cup last-16 victory over Preston North End on Wednesday evening.
Mikel Arteta is optimistic that Gabriel has avoided a major problem, but his status for Saturday's game remains unclear, while none of Martin Odegaard (ankle), Riccardo Calafiori (knee), Kieran Tierney (hamstring) or Takehiro Tomiyasu (knee) will be available either.
On a couple of brighter notes, William Saliba is now cleared for Premier League action again following his recent ban, while Jurrien Timber was able to play the first half at Deepdale after coming off against Liverpool with cramp.
The pair are therefore shoo-ins for the rearguard on Saturday, while Ben White should also be fine after missing the Preston win as a precaution, and Jakub Kiwior may be given the nod in place of fellow left-footer Gabriel.
Mikel Merino got another 45 minutes in his legs on Wednesday, but the Spaniard - who netted in the stalemate with Liverpool - is at risk of making way as Arteta brings all of Declan Rice, Thomas Partey and Leandro Trossard back into central areas.
The latter could act in tandem with Bukayo Saka and Gabriel Martinelli in the attacking third, as Kai Havertz prepares for one of the most difficult aerial challenges he could face in Dan Burn.
Arsenal possible starting lineup:
Raya; White, Saliba, Kiwior, Timber; Rice, Partey; Saka, Trossard, Martinelli; Havertz