Blues completed the loan signing of teenage Manchester City attacking midfielder Albert Rusnak on 21 January 2014.
The 19-year-old Slovakia U21 international moved to St. Andrew's on a one-month youth loan up to and including Saturday 22 February.
The forward, whose preferred position is the 'number ten' role, has been with City since moving to the Etihad Stadium from Slovakian side MFK Košice in 2010.
A regular for City's Development Squad, he has yet to make a competitive first-team start for the Barclays Premier League title-chasers.
However, earlier this season he spent a short spell out on loan at Sky Bet League One side Oldham Athletic, where he made three appearances for the Latics.