It's been made very clear over the summer that Arsenal are lacking in the defensive department.
Even before the season started, the majority of Arsenal fans would have told you they'd like the club to land a new centre-back, but those desires strengthened following injuries to Per Mertesacker and Gabriel Paulista.
The German international will be out for a few months following a knee injury, whilst Gabriel will miss the next six to eight weeks following a serious ankle injury sustained in the final pre-season game.
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Injuries to the centre-back duo leave Arsenal with just Laurent Koscielny and Rob Holding as fit and recognised central defenders, but with the latter recently arriving from League One side Bolton Wanderers, there are doubts over whether he's ready for the first-team.
Calum Chambers can play at centre-back, but since arriving from Southampton, he's failed to impress and often looks uncomfortable when playing at the heart of the back four.
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Arsenal boss Arsene Wenger has been adamant throughout the summer that he is active in the transfer market and will sign when, and if, the right player becomes available.
The Frenchman always has a strong opinion about the window and always says there is no point in signing someone just for the sake of it.
However, it's very clear that Arsenal are lacking depth in defence, and a centre-back is certainly needed before the end of the transfer window.
Shkodran Mustafi has been heavily linked with a move to the Emirates Stadium in recent weeks, but Valencia seem adamant that he's not for sale.
Arsenal possibly missing out on the German has surprisingly seen them target West Bromwich Albion centre-back Jonny Evans, but a £25 million price tag will almost certainly put Wenger off any potential deal.
With Mustafi and Evans now looking unlikely, Wenger and co. may have to start looking elsewhere, and according to the Daily Mail, AS Roma centre-back Kostas Manolas is the latest on their radar.
Arsenal have been linked with the Greek international ever since his Olympiakos days, but after replacing Mehdi Benatia at Roma, it was another target that Wenger missed out on.
However, an Arsenal scout was at Roma's Champions League qualifier last night against FC Porto and was reportedly casting his eye over the Greek international.
The Serie A side fell to a 3-0 defeat and also had two men sent off during the qualifier, with Arsenal's Wojciech Szczesny going missing for the second goal.
Despite the poor night for the Italian outfit, Manolas has been a valuable addition to their team over the past couple of seasons.
The 25-year-old joined the club back in 2014 and has gone on to make 68 Serie A appearances for them, becoming a crucial figure in their starting XI.
The 6ft 1" centre-back is very similar to Arsenal centre-back Koscielny.
He's pacy, which enables him to keep up with smaller, faster attackers, and he's also a presence in the air which helps him deal with crosses and taller strikers.
Below you can see a couple of videos highlighting Manolas' abilities.
With Arsenal in dire need of signing a new centre-back, Wenger could do a lot worse than Roma's Manolas.
Would Kostas Manolas be the answer to Arsenal's problems? Have YOUR say in the comment section below!