If koulibaly goes to Chelsea, he's first choice on the left hand side in a 4 or 5.Thiago silva is 96 years old but he's still going to play the big games so that basically closes off Ake's path to be undisputed first choice, if he's going there as a squad player, he's likely going to get more opportunities but not really that much more to justify leaving the back to back champions.
Really hope he stays, the squad has a lot of players who are as yet unproven in a city shirt. For one reason or another, the likes of haaland, alvarez, Grealish, Palmer, Mcatee, Phillips, ortega and potentially cucurella are all still to show Pep they can be trusted, the one area we are currently sorted in is defence, we don't need the upheaval at the back once again with so much settling in happening further up the pitch.