Both clubs have agreed a fee with WBA and Cardiff have agreed terms with the player. Now his agent is checking out what Southampton have to offer.
"We've been very impressed with what Cardiff have had to say - they could not have made Darren feel more wanted," Said David Cody.
"But this is a big decision because he loves life in the Midlands where he is very settled. Whatever happens he will have to move and that makes the decision all the more significant.
"I am speaking to Southampton today about one or two matters and if they are satisfactory, then Darren will speak to them."