Amid speculation that Tottenham are ready to hijack their attempts to land the 26-year-old Belgium international, Press Association Sport understands the south coast club are hoping to steal a march on other interested parties having already entered into negotiations with the Spanish outfit.
Alderweireld, who joined Atletico from Dutch club Ajax in September 2013, spent last season on loan at St Mary's and made 26 Barclays Premier League appearances, all of them starts, as the Saints finished in an impressive seventh place.
Manager Ronald Koeman is keen to retain his services, and while any deal may prove complicated, he is optimistic.
Speaking earlier this week, Koeman said: "The player likes to stay, we like to keep the player but it's a little difficulty at the moment with Atletico Madrid
I have a good hope he will stay for Southampton."
The Saints prospered last season despite significant changes in their squad following the summer departures of Rickie Lambert, Luke Shaw, Adam Lallana, Dejan Lovren and Calum Chambers, and the manager will hope for less of a turnover this time around amid uncertainty over the futures of Alderweireld and midfielder Morgan Schneiderlin.
Source : PA