Arsenal are allegedly targeting West Ham United's Winston Reid and Celtic defender Virgil van Dijk as options to strengthen their defence in January.
Arsene Wenger has reportedly shown interest in both players before, but failed to bring either defender to the Emirates.
The Gunners will be looking for plenty of defensive replacements, especially as first-team centre back Laurent Koscielny is likely to be sitting out for up to four weeks with tendinitis.
Per Mertesacker is the only fit senior central defender for the North London side as their injury list grows.
Wenger recently described his side's latest Champions League performance against Anderlecht as "hugely disappointing" after his side gave up a three-goal lead with 30 minutes remaining.