The point about Robson and Embleton being unlucky with injuries is valid and it seems to be a very common thing for a young player adjusting to senior football suddenly finding that the rigors of it take their toll on their bodies in the early period of transition. Some come through this and some don't. Hume seemed fairly brittle when he first broke into the team but looks stronger now, Maja didn't really struggle with the physical step up.I don't think any of us know, though it is worrying that very two managers now haven't really given anyone other than Hume (and Maja) a chance.
The counterbalance is that a) our managers have been under terrible pressure and that isn't a good context for focusing on youth - if your target is mid-table and you're delivering on it (i.e. if we get up, hopefully) then that's a bit more helpful. And, secondly, some of the youngsters that have been brought into the first team squad - Robson, Embleton - have had terrible luck with injuries.