He'll be starting for Chelsea next year imo, definitely replacing Terry in the squad.
They have Ake(who they brought back from loan in January), and Zouma who are with the squad, training with the squad, and playing right now while Christensen plays in Germany and has said he wants to play full time. I think Ake and Zouma would be ahead of him. They will start year with the same back 3 (Luiz, Cahill, Azpilicueta) as well so him replacing Terry isn't 100% going to happen.
In my opinion he is a solid target for us to be going for. His team mate, Elvedi, is also a good target.