Unai Emery missed the chance to rectify Arsenal's defensive problems in the summer, according to former Gunner Charlie Nicholas.
The Spanish boss is coming under increasing pressure in his role, with the North Londoners slipping out of touch with the top four in the Premier League as they've won just one of their last five top-flight games.
They also exited the Carabao Cup to Liverpool last week, and conceded a late goal to draw 1-1 at Portuguese side Vitoria in the Europa League on Wednesday afternoon.
Following the departure of Laurent Koscielny ahead of this season, Emery has used the likes of David Luiz, Sokratis Papastathopoulos, Rob Holding, Calum Chambers and Shkodran Mustafi at centre-back this season.
The Gunners did sign youngster William Saliba in the summer, but he has been loaned back to Saint-Etienne.
But Nicholas says that Emery should have moved for England internationals Chris Smalling and Gary Cahill, with Smalling joining Roma on loan from Manchester United and Cahill making a permanent switch from Chelsea to Crystal Palace .
"Arsenal don’t sign personalities," Nicholas told Sky Sports .
"Sadly I have to go way back to David Dein and he would sit down with Arsene Wenger and ask what kind of character he was signing. That’s gone now.
"It’s as if Arsenal sign players because they are desperate.
"Why not – and I don’t know how much he would have cost – go and get Chris Smalling from Manchester United in the summer before he went to Roma? Because he’d be better than what they had.
"They could’ve had Gary Cahill from Chelsea and sat him in the defence.
"He is better than what they have and is also a leader, but they missed out."
The Gunners go to Leicester in the Premier League on Saturday, when a defeat could leave them nine points outside the top four.
