I would take a 'younger' Steven Caulker now, he went to Yeovil as an 18 year old, then moved up to Bristol City and then Swansea, and is now finding his way into Spurs first team squads and International recognition.
What about Scott Wootton at Man Utd, played on loan for Tranmere, Peterborough and Forest so far, aged 21. Or someone a wee bit younger, Nicholas Ioannou, 18 years old, again at Man Utd, Cypriot with bags of potential.
Over at City, Kieran Kennedy, local centre half, 20 years old this September, capped by England u19's.
But one who could really ruffle some feathers is City's u18 captain George Swan, Peter's son. George was on Leeds's books before City.