Arsene Wenger has conceded he may need to reinforce his squad in January, following Sunday's loss to Manchester City.
Arsenal are already short on full-backs with Carl Jenkinson, Andre Santos and Bacary Sagna sidelined for significant periods, and also lost Johan Djourou at the Etihad Stadium.
The Swiss defender is expected to be out of action for around three weeks with a groin complaint, and provides Wenger with another selection headache.
The Gunners boss is already contemplating bolstering his forward ranks with Gervinho and Marouane Chamakh set to fly off to the Africa Cup of Nations in the New Year.
And, says Wenger, additions at the back may now be required when the transfer window opens next month.
"We hope to have (Jack) Wilshere and (Abou) Diaby back so in midfield we have the numbers required," he told Arsenal.com.
"But at the moment we are short at the back and if Gervinho and Chamakh go to the Africa Cup of Nations we are short up front more than midfield."