Unless you're dealing with a genuine reader of the game out of defense (whether that's backed up by phenomenal athleticism or not, ala Desailly or Campbell) I would be extremely wary of paying that kind of money for a CB who is likely to be leaving his athletic prime in the near future, unless a freak of the ilk of a Giggs, Zanetti, C.Ronaldo kind.
Further to that, adjusting to a harder, faster league where the likelihood of being pushed harder on a game by game basis, as well as playing more than used to... it's a move wrought with danger and risk as that asset cannot be moved on for anything like the price bought for.
I've nothing against Koulibaly - he's routinely regarded as an elite CB - , and he may well move and have a flawless, injury free, exemplary run of games, but we're in such a critical period of rebuilding that we have to take so much more into consideration than if he were just a great player coming into an already great squad - for the amount of shuffling about of our surplus CB's and the amount of eggs then placed squarely in his basket, it is one hell of a roll of the dice for us to make at the present time with so many other positions in dire need of thorough address at a cost going comfortably into the nine-figure territory.
Further to that, adjusting to a harder, faster league where the likelihood of being pushed harder on a game by game basis, as well as playing more than used to... it's a move wrought with danger and risk as that asset cannot be moved on for anything like the price bought for.
I've nothing against Koulibaly - he's routinely regarded as an elite CB - , and he may well move and have a flawless, injury free, exemplary run of games, but we're in such a critical period of rebuilding that we have to take so much more into consideration than if he were just a great player coming into an already great squad - for the amount of shuffling about of our surplus CB's and the amount of eggs then placed squarely in his basket, it is one hell of a roll of the dice for us to make at the present time with so many other positions in dire need of thorough address at a cost going comfortably into the nine-figure territory.