Been doing just fine without him this season. Ainsley Maitland-Niles could maybe, if needed, play the occasional game there.
Anyway, I was mostly talking about next season. Assuming that Chambers comes back and that Holding doesn't go on loan, then you've got way too many centre backs. Even if Chambers would come back as a second choice right back instead of as a cb, then it'd still be the same problem.
Why not just give more minutes to players like Holding and Chambers instead? Chambers is pretty good, can (and most likely will) become better if he's given more chances. I'd the same about Holding based on the little I've seen of him. There really is no risk involved here.
The club needs to do better long term planning and extending contracts of (sometimes old) squad players with zero room for improvement, to give them minutes that should be given to younger players, whilst also ignoring/failing to strengthen the positions required, is not really what I think is good long term planning.
A left back, a central midfielder and a winger, is something that should be signed during the summer, but I don't see how there could be any room for that now.
edit: Also, in case of an injury, I can't say I'm a fan of replacing either of the two starters, with their playing styles and what that brings to the team, with a slow penalty box defender who is not very good at playing out from the back.