Unai Emery has tended to deploy a back-three of late but must either re-think his system, put players out-of-position or make a last-ditch signing to cover the shortfall.
Shkodran Mustafi is the only full-fit senior centre-back available.
Konstantinos Mavropanos, 21, has not played a single minute under Emery while Nacho Monreal and Ainsley Maitland-Niles might be required to occupy a central role.
Alternative options include Mohamed Elneny and Granit Xhaka who have each played in defence in dispatches this term, or summer signing Stephan Lichtsteiner.
Options in the Under-23 squad include Julio Pleguezuelo, Daniel Ballard, Zech Medley, and Joseph Olowu.
And the youngsters might have to be considered.
The Gunners face Cardiff City on Tuesday but supporters are more concerned about the prospect of taking on Pep Guardiola's side at the Etihad Stadium at the weekend.
City have plundered 62 Premier League goals this term and are breathing down the necks of Liverpool, who are just four points ahead at the top.
Reddit user dead_siaf said of the trip to Manchester: "We'll be lucky to concede five goals only."
Bigjmert added: "Would rather forfeit and take the 3-0."
Skool_101 was similarly pragmatic, insisting: "Hoist the white flags!!!"
And PhillipLlerenas genuinely entertained the idea of avoiding the game altogether.
He said: "Seriously tho...has that ever happened? Has a team ever made a calculated decision to forfeit to either avoid humiliation or avoid an inevitable goal difference destruction?"
are handed an automatic 3-0 defeat.
The Football Association could even look to increase the reprimand if they see fit.
Arsenal have lost their last four meetings in all competitions with City, including last season's Carabao Cup final.
Their last top flight success came back in December 2015, when they ran out 2-1 winners at The Emirates Stadium thanks to goals from Theo Walcott and Olivier Giroud.
And it is just over four years since Arsenal last won at the Etihad, when they claimed a 2-0 success with Santi Cazorla and Giroud again getting on the scoresheet.