The Brazilian centre-back made a shock move to Arsenal from Chelsea this past summer.
Former Arsenal star Paul Mariner has slammed the club's decision to bring David Luiz to the Emirates Stadium, admitting that he 'thought it was a joke' when he heard his old club had signed him.
Unai Emery's side could be nine points adrift of the Champions League places this evening following last night's abject 2-0 defeat at Leicester City.
Arsenal have now conceded 17 times in 12 Premier League games, giving them a goal difference of minus one.
There is no sign of Emery improving a defence that was supposed to be bolstered by the £8 million addition of Luiz this past summer.
The Brazil centre-back has been known for his erratic defending throughout two spells with London rivals Chelsea.
And Mariner, who spent two years at Arsenal, admits that he couldn't believe when he heard the news of Luiz's move to the Gunners.
He told ESPNFC: "Everybody knows the back four is absolutely useless. We've been asking him to sign quality defenders for well over a season, and what we get is David Luiz?
"I'm deadly serious - when that came out that we signed Luiz, I thought it was a joke. He's not going to be a solution. He's part of the problem."
Luiz certainly hasn't shored things up in a defence that continues to leak goals.
The worrying thing for Arsenal this season is that they aren't scoring regularly either. Emery's side have found the net only 16 times in the Premier League - the same amount as 17th-placed Aston Villa - and there's huge pressure on the Spanish coach.
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