If Pocchettino is to persist with a back 3, I'd certainly look to acquire a third starting centreback to play next to the Belgians, plus maybe a veteran who's willing to be rotated in; Dier's not up to it.
Michael Keane is the most obvious fit, with only a year left on his contract, and his years in the lower leagues have galvanised his all-round defensive capability, something CCV should be exposed to. Wimmer can be disposed of for a decent price, with Davies given a fair crack at rotating with Jan to keep Vertonghen fresh.
Dier might just find himself in limbo this summer; adore him as a midfielder and would personally build the team around him, but it's clear Wanyama and Dembele have been promised the midfield when fit, and the emergence of Winks plus potential arrivals of Barkley/Tielmens might further limit his opportunities.
Mourinho is meant to be a big fan, and rather than take £35m cash to play some more transfer roulette with, it'd make more sense to engineer a swap with Martial, a player who'd justify the sacrifice and immediately improve the first 11 here; he's got Balon D'Or potential in the right environment with the right coach.
