Kyle Walker another expensive City defender but where are the bargains?
It seems something of a paradox that Manchester City now possess three of the four most expensive defenders in football history following the capture of right-back Kyle Walker from Tottenham Hotspur.
City have been spending big on defenders for years, but they look no closer to becoming the strong defensive unit that the transfer fees suggest they should be.
There remains some uncertainty over the exact fee that City paid for Walker, with one side suggesting a deal worth up to £53 million and the other insisting it was no more than £50m, but it's a matter of loose change considering that the England full-back is now either the game's costliest-ever defender or merely the joint-record holder with David Luiz, who cost Paris Saint-Germain £50m when he left Chelsea in 2014.
John Stones, at £47.5m, is next, followed by Eliaquim Mangala, City's forgotten (and unwanted) man, who cost £42m when he arrived from FC Porto in 2015.
By the time City complete a deal for Monaco left-back Benjamin Mendy, who is likely to command a fee in excess of £40m, Pep Guardiola will be able to count on four of the top five in the world's most-expensive defender list.
Nicolas Otamendi, at £31.5m, is not far behind Arsenal's Shkodran Mustafi (£35m) and PSG's Thiago Silva (£33m) in the top 10, so on the face of it, Guardiola has an array of high-end players to choose from when it comes to keeping the ball out of the City net.
The unfortunate reality for Guardiola, however, is that his best defender remains an injury-ravaged centre-back who cost a mere £6m when arriving from Hamburg in August 2008. Vincent Kompany, the City captain, is the perfect example that a pricetag does not automatically define a player's value to a team.
Had Kompany been fit enough to play more than the 11 Premier League games he was able to participate in last season, the doubts over Stones' progress may not now be so prevalent and City might just have pushed Chelsea harder and longer in the title race.
At 31, Kompany is by no means a veteran, but his fitness record in recent seasons has progressively deteriorated to the point that Guardiola cannot rely on the Belgian to be fit when he needs him most.
Just as Rio Ferdinand and Nemanja Vidic were cut down by a catalogue of injuries at Manchester United during their later years at Old Trafford, Kompany has become a player who misses more games than he plays, but his team and defence look a lot better when he is there.
The City captain remains the outstanding defender at the Etihad Stadium and it would be interesting to know exactly what he thinks of those players brought in to either replace him or play alongside him.
Mangala has been written off by Guardiola -- he didn't sign him, so discarding the Frenchman has been an easy decision to make -- but he looked impressive when he began his City career alongside Kompany.
Strong, quick and athletic, Mangala appeared to be a perfect foil for Kompany, but once the captain was out of the team, Mangala's poor concentration levels were exposed and he has never recovered.
Stones is another with great qualities but, again, without Kompany's presence and guidance alongside him, the England defender is careless in possession and lacks the experience to steady himself.
Added together, Stones and Mangala cost City almost £90m, which is a lot of money for two defenders who look distinctly average when Kompany is not there to hold their hands.
By signing Walker, and potentially Mendy, City are at least adding players who have performed in the Champions League and at international level. They have more experience than Mangala and Stones, so they should not suffer the same issues or dips in form.
However, City are beginning to look as though they are simply throwing money at a problem in the hope, rather than expectation, that it works.
There is value to be found in the market when it comes to defenders, but City seem to want to go straight to the top shelf and pick the players with the biggest pricetags.
Toby Alderweireld was arguably the best defender in the Premier League last season and he cost Spurs just £11.5m two years ago. At the same time, Mauricio Pochettino spent £3.5m on Burnley right-back Kieran Trippier -- a homegrown player discarded by City in 2012 -- who was picked above Walker to play against Man United and Arsenal towards the end of last term and won an England cap.
Eric Bailly cost Manchester United just short of £30m last summer and the Ivorian was excellent last season, while Liverpool picked up Joel Matip on a free transfer after astutely exploiting his contractual situation at Schalke.
For some reason, City have lost the ability to be similarly smart in the transfer market. Perhaps it is due to the vast wealth of owner Sheikh Mansour bin Zayed al Nahyan, but there have been precious few bargains arriving at City in recent years, certainly not in the same bracket as Kompany, who must go down as one of the club's best-ever signings.
Big transfer fees are no guarantee of success for any player and City have discovered that with their defenders.
Mark Ogden is a senior football writer for ESPN FC. Follow him @MarkOgden_