The 20-year-old South Korean international is under contract with the Bundesliga outfit until 2014, but with less than 18 months to run on his existing deal, he is refusing to sign an extension.
Spurs boss Andre Villas-Boas has been credited with an interest in bringing Son to White Hart Lane, as the Portuguese tactician considers strengthening his attacking options this transfer window.
A versatile forward, who can operate on the right wing as well as through the middle, Son is regarded as one of the brightest young prospects in all of Germany at the moment, and has attracted admiring glances from a number of clubs around Europe.
Two weeks ago former Tottenham star Rafael Van der Vaart - now a team-mate of Son's at the Imtech Arena - told German newspaper Bild, that his old club would be interested in bringing the attacker to north London.
"Spurs are always searching for the best young talent – that is why every year they are near the top," he said.
With six goals in 16 appearances this season prior to the winter break, the Asian star's potential is clear, and could prompt Tottenham to raid the German market again, having already secured the signature of Schalke midfielder Lewis Holtby, who signed a pre-contract agreement to join the club this summer, earlier in the transfer window.