Teenage centre half Dan Preston has become the latest addition to the Blues first team squad.
The player who turns 18 next Saturday, has been given the number 30 shirt by boss Alex McLeish.
Blues have been hit hard by a mounting injury crisis in recent weeks, which has seen no less than 12 players unavailable because of injury.
On Saturday against Hull, McLeish was only able to name six substitutes, instead of the maximum seven allowed.
Preston, who grew up in Kings Norton and is a second year scholar, has been with the Blues Academy for the past seven years.