At the club at the moment? Dier, but as I mentioned, he's a suboptimal solution.
The ideal 'cat' to partner Romero would be the following -
a) left-footed or is used to playing on the left;
b) excellent at spreading play and long passes;
c) a good organizer;
d) good in the air;
e) reasonably mobile; and
f) comfortable drifting out to the flank if necessary (to cover for Reguilon).
The few players who fit *all* those categories (Alessandro Bastoni, Lucas Hernandez, Presnel Kimpembe, Mario Hermoso, Laporte) are out of our reach. A level below are players like Sven Botman and Pau Torres, but they have their own issues - Pau is a bit physically underwhelming for his size and has looked shaky on international duty, Botman is slow and a bit immobile. A further level below would be players like Clement Lenglet (coming off a bad year, confidence a bit shaky), Evan Ndicka (seems better in a three than a two), Benoit Badashile (only 20) and Marcos Senesi (coming from the Netherlands, always a bit of a risk).
So, on the market, if we were to look for a 'cat' to partner Romero, we'd have to make compromises on some of those ideal qualities. Close to the top of my list, though (if not at the top of it), would be Edmond Tapsoba - while not left-footed, he's used to playing on the left of the back line for Leverkusen, is a truly magnificent passer (his pass progression stats are routinely comparable to advanced midfielders), and routinely wins his defensive duels in the box and uses his magnificent pace to cover his defensive partners.
He's not the type to constantly communicate and organize from what I've seen, but of all the options out there, he's probably my top, barely-gettable pick.
