Former Arsenal midfielder Emmanuel Frimpong has urged the Gunners to move for Napoli centre-back Kalidou Koulibaly.
Unai Emery's side have already shipped 10 Premier League goals this season, with summer arrival David Luiz failing to impress alongside Sokratis Papastathopoulos in central defence.
Frimpong has claimed that Koulibaly is the type of player that his former club should be targeting if they are to challenge for the major trophies once again.
Meanwhile, the 27-year-old has said that he sees "little difference" between Luiz and Shkodran Mustafi, who is yet to make a Premier League appearance this season.
"I watched the game against Watford and it wasn't good. Our defence is certainly weaker, when you compare it to Liverpool or Manchester City," Frimpong told Meta Ratings.
"David Luiz has been making some mistakes, and in my opinion, there's little difference between Luiz and Mustafi; I would rather see Callum Chambers selected. They need to be buying better defenders, like Koulibaly, who can make a big impact on Arsenal's team."
Both Barcelona and Real Madrid have recently been linked with moves for Koulibaly, who is believed to have a £110m release clause in his Napoli contract.
