Defensive is a state of mind. Look at last year's team, they had to not only learn how to play defense but buy into it.
The only real difference this coming year, is that we have a few players that are/were known in HS as defenders. Similar to how MKG, Davis, Noel, etc. were coming into college. For example, Monk was NOT considered a defender in HS but obviously possessed all the tools to be a great defender.
Plus, SKJ, Diallo and WG are all well aware that they have to play D at UK and have technically learned teh system and all have the tools to be elite defenders. Diallo literally has the tools to shut down any kind of player, it is almsot scary. Heck WG does too.