I don't remember Walker specifically in that match (I was a bit dazed and confused by their second goal...), but I've definitely said that about him previously - IMO his lack of defensive play let in the goals which got us knocked out of Europa last season.
Which isn't intended to blame him per se, as you say he's still young yada yada yada and I do think that 1) he's improved shedloads over the last year, and also 2) the winger has a duty to support him as a 'new' player, he just needs to remember that his first responsibility as a full back is to defend. It must also be a tad confusing when he's learning his trade that managers want to use the speed of youth for attacking too; I don't remember having the same issue with BAE, but he's the only FB I can think of who's not had an issue with that when learning.
I'm not sure any of the above reads as actual sentences, I'm feeling the effects of yesterday's celebrations a bit...
