I think our experience in getting world-class surgery and rehabilitating players, especially from major injuries, will bring Rico back to be our first-choice left back and regain England selection. Clarke and Barbet have shown they can deputise there, so retaining one will give us cover, and only the coaching staff will be able to assess the potential of Field and Chatzitheodoridis.
What we lack is experience and the players we retain will all have another year ticked off. From the experience point-of-view, Bjelland moving on will be a serious loss and Judge must be a serious doubt to remain. So, there is a open question about bringing in a more experienced player, possibly as a centre back. To me, that issue was brought into focus against Barnsley, where the serious lack of any leadership on the pitch, allowing players to play as purposeless individuals and beat themselves up when they made errors.