I wonder if it's a case of waiting for him to develop a bit more physically more than anything, because the way he plays, he is going to get the shit kicked out of him and he won't be protected by the refs. Might need to build up his core strength etc, help protect him against injury.
The closest player to Foden to come through in England is Wilshere, and his career has been wrecked partly by injuries. Not sure the specific causes of his, but he did used to regularly get a kicking from a young age.