This has always been Pep's blind spot – failing to adequately replace defenders, thinking that by sticking one of his many surplus midfielders there together with his genius tactics, he can always plug the gap. His Bayern got eliminated from CL each Spring because they were paper-thin at the back at a crucial time and there were signs of neglect of this position at Barcelona already, like preferring a converted midfielder to the great Carles Pujol. 2 seasons ago we repeatedly took advantage on Delph's weakness at LB; now they have a similarly suspect Zinchenko at LB and no fit CBs bar Otamendi. They are already conceding the largest % of goals in the league from set plays. This Man City team are almost perfect in every other department, but this is a clear weakness that was exposed by Norwich and hopefully more and more opponents will learn to exploit it.