Emery has done this as well at Villarreal to a degree, with Foyth at RB. With Pep utilizing it to great effect, others will begin to copy. I'm convinced it's why Emery wanted Torres, we now have 4 good CBs and can play a back four with 3 centre backs and one full back or a back four with 2 centre backs and 2 full backs.
We've seen it in pre-season, both sides:
vs. Fulham:
Carlos -- Konsa -- Tores ------------
-----------------------------------------Digne
vs. Brentford:
----------- Konsa -- Mings -- Torres
Cash ----------------------------------------