We're obviously missing Stones, not only for his play, but also because other players are having to play every game.
Under normal circumstances, Walker and Akanji wouldn't have been playing this many games so far and it looks like they're tired and need a rest.
I think we've missed Laporte and Cancelo also.
Gvardiol will, eventually, be a more than adequate replacement for Laporte, but we haven't replaced what Cancelo gave us and in both areas it's become more noticeable as the season has gone on.
We need to buy a proper left back.