Fellow defenders Laurent Koscielny (Achilles) and Dinos Mavropanos (groin) are long-term absentees, further limiting Emery's options.
The only good news for the Spanish coach is that he will have utility man Ainsley Maitland-Niles to call upon once more after he made his return from injury in Wednesday's EFL Cup fourth-round win over Blackpool. Maitland-Niles is likely to start at left-back if neither Monreal nor Kolasinac is passed fit.
Elsewhere, Matteo Guendouzi is suspended after his sending off against the Seasiders, while Mohamed Elneny is two weeks away from making his return from a thigh injury.
Aaron Ramsey and Mkhitaryan Henrikh will be hoping for recalls after starting last week's draw with Crystal Palace on the bench as Arsenal go in search of their first win over Liverpool in seven meetings.