It was thought that Fulham, who are known to be interested in the Vitesse Arnhem left back, would lead the pack but upon visiting Saints' training setup, Buttner believes his future is red.
"I want to go to Southampton," he told De Telegraaf. "I have to wait for both clubs to reach an agreement, but I count on the co-operation of Vitesse."
After turning down a bid of around £1.6 million from Fulham, Vitesse are the only obstacle for Buttner, who suggests his preference for Southampton stems from their ambition.
"It would be a massive blow if this won't go through," said Buttner, who is under contract with Vitesse for one more year.
"I have been to Southampton and everything - including the living conditions - are perfect. The club, the stadium, everything, surprised me. Fantastic.
"And Southampton have big ambitions. With the new investor they want the same as Manchester City."
I'm not quite sure Buttner is Man City standard but he can only dream.