Che Adams moved to Blues in August 2016 from Sheffield United for an undisclosed fee.
The Leicester-born player, who can operate as an attacking midfielder or striker, penned a three-year deal at St. Andrew's.
He made 54 appearances for the Blades after making the switch from Ilkeston in 2014, scoring 15 times.
The former England U20 international started his playing career at non-league Oadby Town before his rapid rise up the football pyramid.
Adams made his Blues debut in the 1-1 Championship draw away at Wigan Athletic on 16 August 2016.
During his first season at St. Andrew's, Adams made 42 appearances and scored seven goals, including the crucial final-day winner at Bristol City which kept Blues in the Championship.