Arsenal manager Arsene Wenger has been forced to rush vice-captain Per Mertesacker back into first-team contention ahead of schedule for tomorrow night's Champions League qualifier against Besiktas, with the German international travelling to Turkey with doubts persistent over Laurent Koscielny's fitness.
Koscielny has been struggling with an achilles problem but still started and scored against Crystal Palace in Saturday's Premier League opener at the Emirates, although despite playing 90 minutes in that clash remains a doubt to feature at the Ataturk Olympic Stadium.
Gibbs adds to injury problems
Wenger has yet to sign a suitable replacement for Thomas Vermaelen and as a result looks short of defensive options for a crunch clash with Besiktas, a situation not helped by Kieran Gibbs suffering a recurrence of a persistent hamstring complaint against Palace.
Gibbs joins David Ospina, Serge Gnabry, Ryo Miyaichi and Theo Walcott on the sidelines, which means with Abou Diaby still working his way towards towards full fitness means Wenger is without six potential squad options regardless of doubts over Koscielny.
Nacho Monreal will deputise at left-back, but unless Koscielny passes a late fitness check it could be a far from fully fit Mertesacker alongside impressive youngster Calum Chambers.
Further forward Wenger will be tempted to juggle an attack which struggled for long spells to break down a stubborn Palace on Saturday night, with Olivier Giroud definitely in contention to replace Yaya Sanogo.
Santi Cazorla and Alexis Sanchez played on the flanks in that 2-1 win but found fluency difficult to come by, which could mean first starts of the season for either Joel Campbell or Alex Oxlade-Chamberlain in their place.
Turkish opposition for second season running
The Gunners will come up against a familiar foe in the Besiktas attack, with Demba Ba leading the line and in fine form after scoring a hat-trick against Feyenoord in the last round of qualifying.
Besiktas coach Slaven Bilic could be without Atiba Hutchinson from the side that eased past Feyenoord, but former Arsenal academy standout Oguzhan Özyakup is in contention to face his former club desptie serving a two-match domestic ban in what promises to be an intriguing tie.
Arsenal: Szczesny, Debuchy, Chambers, Koscielny, Monreal, Arteta, Wilshere, Ramsey, Sanchez, Oxlade-Chamberlain, Giroud
Besiktas: Zengin, Kurtuluş, Franco, Gülüm, Motta, Frei, Kavlak, Uysal, Şahan, Pektemek, Demba Ba