Zigic arrived at St Andrew's last summer from Spanish outfit Valencia for £6million.
But the towering 6ft 8in Serbia international has scored just four goals in 25 appearances and struggled to command a regular starting spot in manager Alex McLeish's first XI.
On his way: Birmingham striker Nikola Zigic is wanted by his ex-club Racing Satander
Santander are ready to launch an ambitious bid to resign the 30-year-old, who first signed for the La Liga club in 2006 from Red Star before returning for a loan spell in 2009.
The Spanish outfit were taken over by wealthy Indian businessman Syed Ali last week, who is determined to use his financial clout to make the club one of the most dominant on the continent.
Heading off: Zigic has reportedly failed to settled in England since his arrival last summer
He said in a statement: 'I look forward to an active and long-term commitment to this great club and will invest all my knowledge and financial strength to elevate the club to the highest level of success in Spain and Europe.'
According to Spanish sports daily AS, Zigic is keen on the idea of cutting short his stay in the Barclays Premier League and returning to Spain since his family, including expecting wife, have failed to settle in England.
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