Vitesse Arnhem have said they have reached an agreement with Saints over the transfer of left back Alexander Büttner.
The Dutch club posted a statement on their website this afternoon.
The Eredivise side claim Saints today submitted an improved offer for the left back, meeting Vitesse's evaluation of the 23-year-old.
It is understood Büttner is now trying to sort out personal terms with Saints before sealing the move.
Fulham, QPR and Werder Bremen have also been tracking the player.
Buttner has made his name with the Eredivisie outfit at left back, even making the provisional Netherlands squad for Euro 2012.
But he has also played as a winger for Vitesse, while he came through the ranks at Ajax as a more central attacking player.
Vitesse have been resigned to losing the player this summer, with Buttner having just one year left on his current contract.
He has been allowed to travel to England to visit interested clubs, including Fulham and QPR as well as Saints.
German side Werder Bremen are also interested, but Buttner has made it clear from the start that St Mary’s is his choice.