Mumorn
Vic Buckingham
And also by your logic, we should probably avoid Jese Rodriguez, as he is already 20 and hasn't done anything in the first team. Or does that one year make that big of a difference? I would much rather go on a case-by-case basis than making big sweeping generalizations that if someone hasn't broken through to the first team by 21 that they are useless.
At least Jese Rodriguez can get into the Spain U20 team and look good. Has Ceballos actually played for Spain at any level or have they realised that he just isn't that good?