Pedro Martins is already having to make do without two centre-backs in Ruben Semedo and Avraam Papadopoulos, while Ousseynou Ba lasted just 18 minutes of Saturday's 3-0 victory over Lima and is expected to miss out here.
Former Arsenal man Sokratis was also seen struggling with a shoulder problem but should be fine for the first leg, but Martins is now in a quandary with regards to who will partner the commanding Greek defender.
Full-backs Mohamed Drager or Jose Holebas could be forced to fill in at the heart of defence, but with midfielder Mady Camara returning from suspension, Yann M'Vila - previously linked with Arsenal several years ago - could be set for an emergency shift at centre-back alongside Sokratis.
Camara is set to reprise his role in the engine room alongside Andreas Bouchalakis, and spearheading the hosts' attack is a player that Gunners fans will be glad to see the back of in a few years' time.
Youssef El Arabi's 119th-minute winner at the Emirates last season saw Arsenal crash out of the tournament at the last-32 stage, and with the 34-year-old already boasting 20 goals for the campaign in all competitions, Arteta's shaky defence must keep an eye on him as he aims to break Gooners' hearts once again.
Olympiacos possible starting lineup:
Sa; Lala, Sokratis, M'Vila, Reabciuk; Camara, Bouchalakis; Valbuena, Fortounis, Bruma; El Arabi