I don't think so either, instincts are all wrong when you drop a centreback in there. White's good at venturing forward because as a defender he gets to push up unmarked most of the time, and it affords him time and space, and at pace, that he wouldn't have otherwise. It's a rather different role to sit in midfield and structure the game.
I dunno, maybe he can do it, but it rarely works out in reality. Petit was able to make that transition for us off the top of my head, and fullbacks like Lahm and Zanetti could make it. Marquinhos is arguably the best I've ever seen at it; bloke could have been a world-class midfielder too if he wanted to. But most defenders struggle to play higher up the pitch. We'd be better off going for a proper midfielder instead, especially considering the state of the squad.
I'd sell Gabriel if a good offer came along and just use the money for a new defender, regardless of whether Saliba comes back or not. Gimme Skriniar this summer.
