Koulibaly is at his best on the left side of the pairing the same as Maguire, it may be a small thing to some but that’s the whole reason Rojo was signed as our centre backs were all right sided.
Either way we don’t need Koulibaly as from what I’ve seen of Serie A which granted isn’t lots is Koulibaly has been poor most of the season and Smalling has been one of the best centre backs in that league, do you want to part with £70-£90 million for a centre back who’s been poor all season and would no doubt take time to settle when we’re stocked at centre back ?
I’d much rather look at a young centre if we’re going to spend big money like Upamecano or Konate or I’d be happy looking at Rodon at Swansea as all three fit the profile we seemingly are targeting, all three would be half the price of Koulibaly and have much more upside.
We’ve got Maguire, Lindelof, Bailly, Tuanzebe, Smalling, Jones and Rojo and even if (as I’d like us too) we got rid of Jones and Rojo we’d still have a stronger group of centre backs than anyone else is the league. We need a right winger (Sancho) and a pure defensive midfielder as priority signings though and not centre backs.