Defender Krystian Pearce has extended his loan spell at Port Vale for a further month.
Parent club Birmingham have given the green light for the centre-back to continue his stay at Vale Park.
Manager Lee Sinnott told BBC Radio Stoke: "He is mature beyond his years and he is learning all the time he is here. We are pleased he is staying."
The 18-year-old, who has made four appearances for Vale, will now stay on at the club until the end of March.