Arsenal have suffered from a disease called "defensive crisis."
In recent years, Arsene Wenger's men have shown that their offense can be brilliant. However, their defense has been very inconsistent, and for some unknown reason, Wenger hasn't signed anyone, except for Finnish Carl Jenkinson from Charlton.
The Gunners' defenders have been very injury-prone; some of them not being able to play, forcing Wenger to play younger, more inexperienced defenders.
Others, like Thomas Vermaelen, haven't been able to play for ages, as the Belgian missed virtually the whole season due to his calf injury.
But it's not only injuries that pose the problems.
Arsenal defenders have also not held their composure in the past, collapsing in crucial moments of the match.
For example in April, when Arsenal hosted a match against Liverpool, it was 0-0, until five minutes into stoppage time, when van Persie scored on a penalty. It seemed certain that Arsenal would win this match.
Then, two minutes later, Liverpool equalised with a Dirk Kuyt penalty after bombarding Arsenal's goal. Though the penalty was unfair, it just showed how the defense allowed such attacks on their goal in key parts of the game.
To prevent things like these, here are five defenders that Arsene Wenger could potentially sign.