Chelsea hero Frank Leboeuf has urged Frank Lampard to sign his own version of Virgil van Dijk.
The Dutchman has transformed Liverpool's defence since joining in January 2018, helping them win the Champions League and Premier League.
Lampard's defence shipped in 54 goals in the Premier League this season, and Leboeuf believes the Blues need a world-class centre-back.
He told ESPN: "[He needs to improve] all of them. That's the problem.
"The goalkeeper is a big issue, but you have to go to the main [issue]. If you're looking at the main issue, it's the central defenders.
"[Kurt] Zouma is doing great, but I'm not confident about [Antonio] Rudiger, I'm not confident about [Andreas] Christensen. I don't know what will happen with [Fikayo] Tomori, but I think they need a big guy.
"You saw what happened with Liverpool when they got Van Dijk, he changed everything. Even Lovren and Gomez looked better alongside him.
"You need a big guy to make sure he'll lead the defence. Look at Ramos. [Raphael] Varane is a fantastic player, but is he still the fantastic player when he plays for France as when he plays for Madrid with Sergio Ramos? He's better with Real Madrid.
"They need a big guy in the centre of defence, yeah."
