Tony Adams has told Mikel Arteta he must give Kieran Tierney a run at left-back rather than continue to play the Scot in central defence.
Arsenal legend Adams also insists Hector Bellerin's defensive skills need to be "worked on" if he is to continue at right-back.
The Gunners' defensive options have come under fire after Aston Villa ran out 3-0 winners at the Emirates Stadium on Sunday.
Bellerin featured as wing-back against Villa; an attacking role he is comfortable with as he plied his trade as a winger as an academy player at Barcelona, though defensive aspects of the Spaniard's performance were called into question.
Meanwhile, natural left-back Tierney featured as the left-sided centre-back in a defensive trio, a role Arteta has frequently utilised him in.
However, Adams believes Arsenal's full-backs are not performing to a high enough level and called on Arteta to coach Bellerin defensively and alter Tierney's role.
The former Gunners captain told Sky Sports: "Every full-back that has come to the club has not been taught to play full-back.
Do you agree with Adams' verdict on how to best utilise Bellerin and Tierney? Have your say here.
"They bomb on as wingers and leave the central defenders isolated, so Hector needs to be worked on.
"Lee Dixon reminds me so much of Bellerin when he first come from Stoke, he would bomb on all day long but we needed to teach him to defend and by the end of his career I think he was one of the best defenders in the world.
"I think Tierney has got it all to me, fantastic attitude. But to keep on playing him left centre-half then left-back, the kid's going to get confused.
"Stick him at left-back and work with him. I think he can be a real talent."
Adams added: "I think Bellerin’s having a tough time on the right-back slot. Going back to the Villa game it was such a poor performance coming off the United game I think Arteta was trying to be too clever.
"He’s gone back into the three, offloaded three with Bellerin making the four in midfield. Tierney is in that kind of too narrow position, he’s a left-back for me."
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