Reports in Portugal suggest Sporting Lisbon are preparing a January raid for Birmingham's Nikola Zigic.
The towering Serbian striker only joined the Blues from Valencia over the summer, but has already seen his future in England called into question.
He has struggled to make an impact at St Andrews following his arrival, but bagged his first Premier League goal in Saturday's 2-1 defeat at Arsenal.
The Blues will be hoping he can kick on from there, but may see their resolve tested once the transfer window reopens in the New Year.
Sporting are reported to have already been in touch with Zigic's agent regarding a deal and are now keen to establish where Birmingham stand.
The Portuguese giants were looking to strike a deal with the 30-year-old forward over the summer, but could not match the offer he received from England.
They are, however, still keen to get their man and are willing to discuss either a loan deal or permanent switch.
Sporting must now wait and see if Birmingham are willing to talk terms, but whatever happens they remain determined to land a new frontman in the winter window.
"We are working on a number of options in the European market," said a club official.