WookieD
Didier Zokora
There's nothing in the rules about minimum age.
No official statement as to who the player in question was or what rule was broken but people thought it was Bentaleb as noone could find his age. Turns out he was 17 which was fine.
One article suggested Liverpool lodged a complaint about 2 ineligible players (Gomelt and Veljkovic maybe who were originally trialists?) whereas Jjetset said it was in the earlier rounds.
As I said above mate, it was either unregistered or underage. Definitely not over age