He'll be fine. It was a bad mistake but every defender has made one at some point. He's still been good enough to deserve to be first choice. We do need cover though. You can tell Rose is knackered and Vertonghen and Naughton are not the answer for cover on the left.
See I disagree, I think his game isn't advanced enough to be first choice yet. I think he either needs to be back up to a first teamer and play against the bottom half of the table or another loan to a prem team. Either way I don't think he is ready for an aspiring cl team. Every other top team has better option so why is it good enough for us?