I take it you mean RB? Robertson and Kostas are very good at LB, so we have decent cover there at last.
I think TAA is very good at RB, but because he is so creative and pushes on, he can be caught of position, Milner is not good enough cover, City targeted him today and he was caught out running back quite a few times, though I though Henderson did not give him much cover either, the whole MF didn't look right and felt second best.
We need better RB cover, Neco Williams was on the bench, so not sure why he was not tried? especially in the Porto game as when we went 3-0 up he could have been given a run out to see how he does.