Arsenal legend Martin Keown urged the Gunners to pull out of a deal to sign David Luiz on deadline day.
The former Arsenal defender believes 32-year-old Luiz is too "high risk" and would leave Unai Emery's men "exposed" at the back.
Arsenal's interest in Luiz emerged late on Wednesday and the Brazilian could seal a shock move to north London before Thursday's 5pm deadline.
David Luiz wants to leave Chelsea before Thursday's deadline
Luiz missed Chelsea training and reportedly went on strike as he looks to force an exit from Stamford Bridge.
But, writing in his Daily Mail column, Keown reckons Luiz would not be the right fit for Arsenal.
Keown said: "If I was at Arsenal and had the ear of Unai Emery, I would be advising my manager not to sign David Luiz.
"Walk away from this deal. This is not the defender for you. It's too high risk.
"The way the 32-year-old plays, he would be exposed in that Arsenal defence. He would not get the same protection that he enjoys at Chelsea, where N'Golo Kante patrols in front of the back line.
Martin Keown is not convinced that David Luiz is the man for Arsenal
"In possession, Luiz is a wonderful passer, but he makes mistakes when playing as part of a back four. He has a tendency to lose his marker and is one of those all-or-nothing players - if he doesn't win the ball in a challenge, then congratulations because you're in.
"Luiz is clearly a big personality. Maybe Emery thinks he can control the Brazilian - they crossed paths at Paris Saint-Germain - but him missing first-team training with Chelsea on Wednesday is a red flag."
The Gunners are also expected to complete a £25m move for Celtic left-back Kieran Tierney on Thursday before the 5pm deadline.