Full backs get right up the line these days and many people still aren't too comfortable with that. Football is generally more fluid these days and players can pick up the ball in positons one wouldn't normally expect them to be in. I expect Shaw has been instructed to be more cautious with Lallana in front of him, but the lad can get forward. Interestingly the lad has played both wings for the youth, but probably mainly for experience like they do with all the kids. Lack of appreciation for the fullback's role I think answers your question.
These days it is more important that full backs can attack rather than defend, defence wise they are expected to shadow the winger and not tackle the guy, generally allowing the slower CBs time to get back. He is just learning his trade but in the last 4 games no winger has caused him trouble so it all bodes well
I can see a massive future for this lad and as he has already shown, he can tackle. As he develops further I think he will be able to start pushing forward occasionally but he is first and foremost a very good defensive left back. I am very content knowing that he is in our team and doing well in that defensive role.
please log in to view this image 23 LUKE SHAW DEFENDER Nationality: English DOB: 12/07/1995 Height: 6'1" (185 cm) Weight: 11st 11lbs (75 kg)
From what I've seen which isn't much of him yet live but he is going to be some player as a full back and we are going to have a serious struggle on our hands to keep him. The top4 will be sniffing around by the end of the season - but the size of the guy and the natural way he defends and positions himself there isn't anything like him in the English game. Cole, Baines and Bertrand are more offensive full backs (not in the rude sense!).