From the outside, Arsenal spending heavily on another defender may seem an unexpected turn in a summer when so much of the focus has been on strengthening their attack. Internally, however, the need for another centre-back had long been established.The roots of the Ezri Konsa signing can be traced back to January, when Arsenal contacted Marc Guehi’s camp. Guehi’s contract with Crystal Palace was due to expire in the summer, and Arsenal were exploring the possibility of adding a third senior centre-half to supplement William Saliba and Gabriel.Guehi chose to join Manchester City in January. Since then, Arsenal’s need for a new centre-half has been exacerbated by the absence of Saliba, expected to miss an extended period with a back injury. After a summer-long pursuit, Arsenal have now signed Guehi’s England international team-mate Konsa, paying £51million ($69.5m) plus £4m in potential add-ons to sign the 28-year-old on a four-year deal from Aston Villa.The Athletic spoke to sources at both clubs and close to the player, granted anonymity to protect relationships, to tell the story of the move.The loss of Saliba crystallised Arsenal’s requirements: they wanted a player with Premier League experience, able to slot straight into the back four.With Jurrien Timber also in rehabilitation after undergoing groin surgery, a player who could also cover at right-back was considered ideal.Konsa ticked every box. What’s more, he’s homegrown: Arsenal currently have 17 non-homegrown players, the maximum permitted in a 25-man Premier League squad.The problem was always price. Arsenal’s initial valuation of Konsa was closer to £40million, with Villa holding out for something like £60million. A compromise was eventually reached at £51million (plus £4m in potential add-ons), with talks at ownership level helping to secure a breakthrough.From the start of the summer, there was a feeling that Villa could be vulnerable to a bid for Konsa. The defender had two years remaining on his contract, and was the most saleable asset at the club outside of Morgan Rogers. Villa had offered a new contract that would have placed Konsa among their highest earners, but it remained unsigned.At 28, Villa were conscious this might be the opportune moment to cash in.Konsa has been a reliable servant to Villa (Jacques Feeney/Offside/Offside via Getty Images)In 2019, Villa paid in the region of £12million to sign him from Brentford. After seven good years at Villa Park, Arsenal’s interest offered the chance to turn a major profit. Villa had planned for this. Joel Ordonez of Club Brugge and Milan’s Fikayo Tomori had previously been two of several players they had identified.Ordonez is admired but would be expensive, so his arrival in this window is being played down. Villa have also had an offer worth £18million ($24.5m) plus add-ons rejected for Southampton centre-back Taylor Harwood-Bellis, but he remains a key target.