How can they not be top four quality when we finished top four last season and we're top four this season.
To repeat my original comment, it’d be nuts to sell any of the current senior centre backs.
We finished top four because the brilliance of our front four (Lallana, Mané, Coutinho, Firmino) in the first half of last season gave us a foothold to hold onto. It certainly wasn't our defence which got us there, even if it did latterly improve with the help of tactical tweaks from our manager.
Why do you think our manager has just spent £75m on a defender? He sees him as an upgrade. Do you think he's sitting there with his feet up thinking "Job Done" now? We could easily upgrade Klavan or Lovren still. The same applies to our goalkeepers, who aren't top four quality either regardless of where we finished last season and sit this season. I don't think our central midfielders are either, hence Naby Keita and probably another in the summer.
It'd be nuts to sell them now, but not in the summer if we bring in someone better, or potentially better. That's literally how the transfer market works.