Birmingham have called 16-year-old midfielder Jordan Mutch into their squad for the FA Cup third round tie at Huddersfield on Saturday.
Mutch had been scheduled to be on the substitute's bench as a 15-year-old for the Carling Cup tie at Blackburn earlier this season.
But under the regulations at the time the former Derby County youngster was deemed too young to participate - although the rules have since been amended.
Blues assistant boss Roy Aitken said: 'One thing with the manager (Alex McLeish) is that right throughout his career his approach has been `if you are good enough, you are in the selection plans'.
'Jordan has come into the group, will go with us to the cup tie, and it will be good experience for him. It also shows all our youngsters around the place that if you are doing well, you will get promoted.
'He has been training with the first team quite a few times. We rate him highly, he is a very promising young player with potential.
'Jordan has shown in recent reserve games the qualities that can make a very good footballer. He is willing to listen and learn, his work ethic is good. He is exactly what the manager looks for in a young player.'
Mutch's chances of being involved could be further enhanced if Mehdi Nafti fails to recover from a viral infection which will be assessed on Friday.
Nafti, Radhi Jaidi and Richard Kingson will be available for the final time against the Terriers before departing for the African Nations Cup.
Meanwhile, former Juventus striker Olivier Kapo is set to rejoin full training from next week after recovering his knee problem.
Kapo is City's joint top scorer with five goals alongside Cameron Jerome.