Koscielny has earned plenty of praise for his recent performances for Arsenal and is widely considered to be one of the best defenders in the Premier League.
The France international has been missing due to injury in recent games but will be hoping to make his comeback for Arsenal when they travel to Barcelona in the Champions League on Wednesday night.
However, former Arsenal man Nicholas has not been as impressed by Koscielny as many others have been this season.
Speaking on Sky Sports News HQ on Saturday afternoon, ex-Gunner Nicholas said: “As Arsenal fans it’s getting tougher and tougher.
“Everybody raves about Koscielny. He’s the best centre back at Arsenal but he’s not a great centre back in my opinion, he never has been.”
“I think that’s always been evident, he [Wenger] has not managed to fill in the gaps that Arsenal need filled in.”
Arsenal were dumped out of the FA Cup on Sunday afternoon after a 2-1 loss to Watford at Emirates Stadium.
The Gunners, who have not won the top fight title since 2004, travel to Everton in the Premier League on Saturday lunchtime.
MORE: The latest football news