Arsenal icon George Graham wants to see money spent on their defence this season.
With Thomas Vermaelen injured since the end of August, boss Wenger has relied on Johan Djourou, Laurent Koscielny and Sebastien Squillaci.
And Graham said: "Arsenal need defensive-minded centre-halves. The full-backs like going forward.
"When the opposition get the ball Arsenal are vulnerable.
"The centre-backs they have look like midfielders. I'm not going to apologise for the way I played. My aim was to get trophies. Chairman Peter Hill-Wood always said before the AGM 'just put a trophy on the table and nobody will have anything to say'.
"I probably wouldn't be in the job if I went six years without a trophy. But if Arsene left Arsenal tomorrow all the biggest clubs in the world would be after him.
"I just think he has gone off the boil a bit.
"I would love him to explain why he hasn't had the success recent and why the team haven't got the edge to win a trophy."
