Sorry; i've said what you've been saying from the start - that he's young, needs time etc. - but i'm starting to think he needs more time in the professional environment before he can start every game. If you don't perform, you don't start - simple.
Problem with that is obviously we don't have any other proven left back, so he's sort of there by default at this point. It's been a little unfair on him to expect him to come in and instantly fix our left back woes.