Pretty much what I said? We need four senior CBs, considering the fact that among the three regular ones we have, one is injury/suspension prone. And out of the remaining lot, I would definitely keep Smalling. I'm not talking about this basis his Italy performances, either. Jones is the better defender, but he has spent more time injured than he has on the pitch, probably. So, yeah, Smalling. He's a decent defender.
Also, the profile we were looking for is a tough defender, able to stand his ground while being decent aerially. Smalling fits the bill. He can't do much else, but eh.
He is not okay being rotation, good on him. That being said, hope we go in for a CB too, if we are sending all of them out. If we actually manage to get 20 Mn for him, that'll be an amazing deal.
Also, Lingard is in the final year of his contract (we have the option of another year), so this is the year to sell him. Same for Mata, although he may move on at the end of the year. If we actually get Lingard, Pereira, Jones, Rojo, Romero and Smalling off the books while bringing in a CB (among others), that'll be fantastic business for the window.