Every time he comes on and does some half decent stuff against tired legs people are desperate for him to be in the first team.
He's 17, his strength and pace are his main attributes, he has a long way to go before we can consider him good enough to play our tactical system against the top sides, he needs a year with the 21's/on loan, if he impresses and develops his game, then start looking at him in PL matches
There is no need nor reason to rush him, we already have Sterling who is a significantly more rounded player