Lol. We're stacked & covered in pretty much every area of the pitch, bar our best & most influential player on the team. Yes Herrera can play there, but let's be honest, he's not half the player of Pogba in that advanced/creative CM role... he'd perform better in Matic's role, or ideally, his best role would be in between Matic & Pogba in a 3... as he's not really a 6, nor an 8, he's a gritty, tidy little balancer, who will follow managers instructions better than most. I'd call him a 6.5, if you get me.
In Pep's system, you can drop KDB & Silva into CM and it'll still flow ever so smoothly, so theoretically, Mata & Mkhi could probably slip into central midfield in a Pep system and relish it based on what you lot are about - silky, moving positional play.. physical aspects aren't a big deal, but in a Jose system; much more direct and powerful, you need your CM's to be much more robust along with all of the creativity required in that advanced CM role. Mata & Mkhi wouldn't excel. This is why Pogba is the perfect player for us, and when he's out, we miss him more than people can imagine.
We need a profile that can effectively cover him. I feel if we had Pereira, a 3 man midfield of Matic-Herrera-Pereira would somewhat compensate his absence. Pereira would have that little creative edge to him (no pushover either mind, for the size of him), and Herrera would be the little wasp he is, mopping everything up. Between the pair of them, they could paper the cracks... mad how you need 2 players to cover one vacancy/role, but that's just how vital Pogba is to this team imo.