Arsenal legend Paul Merson has warned Chelsea risk emulating the Gunners if they fail to fix their defence.
The North London club have struggled for years to solidify their defence, and current boss Mikel Arteta will undoubtedly try to fix the problem this summer.
Chelsea shipped in 54 goals this season despite finishing in fourth, and Merson thinks Frank Lampard must make moves to sign two defenders.
"Their priority has to be getting a centre-half and a left-back. 100 per cent," he told Sky Sports.
"It tells you everything that they have to play three at the back, Frank Lampard doesn't trust the centre-backs.
"They've bought well so far up front, Timo Werner and Hakim Ziyech are major signings, but don't end up like Arsenal, where everyone is crying out and can see what they need. How many years did we say Arsene Wenger needs a centre-half, but he never went and got one?
"Marcos Alonso for me needs replacing; he gets vital goals but he's not a natural defender. That doesn't help the back three because centre-halves have to come out of their comfort zone and come out of the line of the box to defend on the wings. Alonso causes that problem. Cesar Azpilicueta is a great pro, but he's getting on now. Kurt Zouma has a mistake in him.
"Chelsea don't have a naturally-gifted centre-half who can put his foot on the ball and play. I'd go and get John Stones for that, and play him in the middle of the three.
"Then I'd say have Antonio Rudiger and Christensen either side of them. Chelsea love to play out the back, they roll it out every time, so you need someone unbelievably good on the ball. If you have pace around them, I think it will help Chelsea; I think Stones would be a great buy, and he has to play in a three.
"Stones has the potential to be great, he really has, but he needs the confidence. At the moment Chelsea have three centre-halves that aren't in the same class as Stones on the ball."
