The departure of Kyle Walker to Milan sees Manchester City lose their seventh most expensive defender.
But who makes the rest of their top 10? Find out below.
Fees taken from Transfermarkt.co.uk, transfer fees in Euros.
A formidable defender at a still tender age, Josko Gvardiol was signed not just for the present but the future too.
While it's hard for any defender to become a regular fixture in Pep Guardiola's back line, Gvardiol has managed it.
Signed for €71m, Ruben Dias arrived with plenty of expectation on his shoulders, but the Portuguese has more than lived up to it. While he's not yet reached the echelons of the true Premier League greats, he's been a top-class defender ever since his move from Benfica.
The decision to let Joao Cancelo leave looked baffling at the time, with the Portuguese one of the world's best full-backs, but it came at a time when Pep Guardiola realised he needed four top-class defenders, as opposed to flying wing-backs who'd defend when needed.
Although he only managed three-and-a-half seasons in Manchester, Cancelo left with three Premier League winners' medals.
Such were City's defensive riches, they could afford to lose Aymeric Laporte and not be significantly weakened, but he was nevertheless a superb defender during his time at the club. Becoming a starting centre-back, Laporte would suffer a knee injury that cost him his place in the team, but the Spain international fought back to win his place, and left as a five-time Premier League winner.
A part of Monaco's Ligue 1 title winners, Benjamin Mendy left France to join Manchester City for a then-record fee for a defender, breaking the record set less than a fortnight earlier on Kyle Walker.
Although his ball-playing exploits weren't always to Everton fans' tastes, John Stones' ability as a footballer made him a hugely useful tool for Pep Guardiola.
While injuries and the sheer number of defensive options have meant has never started more than 23 games in a season, Stones has still established himself as one of the world's best ball-playing defenders.
While his critics might say that Kyle Walker was overly reliant on his pace, the right-back has been a crucial part of Pep Guardiola's best teams over the years, winning six titles in his first seven seasons with the club.
It appears his City career has now come to an end, but not before more than 200 Premier League starts and a Treble win in 2023.
Initially signed as a squad member from Bournemouth, Nathan Ake played a part in City winning the title in each of his first four seasons with the club.
Ake progressively grew into the squad, with his ability to play left-back and centre-back seeing him played 26 and 29 games in the last two campaigns.
Although Manchester United's scouts described Eliaquim Mangala has a cross between Jean-Alain Boumsong and Joseph Yobo, Manchester City were persuaded to part with £32m for the Porto centre-back.
Struggling to ever really adapt to the Premier League, Mangala is about as well remembered for the scathing assessment by a City fan on Twitter, who told the defender the move had just 'not worked out', as far his on-field efforts.
Signed prior to the Pep Guardiola era, Nicolas Otamendi was one of the few survivors following the Catalan's arrival at the Etihad, and was the starting centre-half for City's 100-point campaign in 2018.