Alderweireld's future at Ajax has been the subject of speculation all summer with the likes of Liverpool, Everton and Norwich all credited with an interest in the Belgian international.
Ajax are facing a battle to hang onto Alderweireld, with the 24-year-old entering the final year of his contract at the Amsterdam ArenA.
Atletico Madrid have firmed up their interest in Alderweireld with a bid, but Ajax director of football Marc Overmars has confirmed they have snubbed Atletico's opening offer for the centre-back.
"We have rejected the offer from Atletico Madrid for Toby Alderweireld," Overmars told De Telegraaf.
"We were contacted this weekend but it was not considered sufficient for a player of the national team of Belgium."