Nicolai Brock-Madsen has returned to Birmingham after failing to make an impact on loan at St Mirren.
The Danish striker did not score in five appearances for the Ladbrokes Premiership side.
The 25-year-old was signed by Alan Stubbs on a loan deal until January with the option to stay for the rest of the season, but he only made one substitute appearance under new manager Oran Kearney.
A St Mirren statement read: “The club would like to thank Nicolai for his contributions and wish him well for his future career.”