Manager Martin Jol is keen to add to his defensive options, and currently only has Brede Hangeland, Aaron Hughes and, Phillippe Senderos as central defenders.
Madlung, who has two international caps for Germany, has fallen out of favour at the Volkswagen Arena and is out of contract in the summer. He moved to Wolfsburg from Hertha Berlin in 2006 and has made over 150 appearances for the club, helping them to the Bundesliga title in 2009.
It is thought that the Bundesliga club will not require a fee for the defender's services in an effort to reduce their wage bill.
Madlung scored against Fulham at Craven Cottage in the first leg of their Europa League quarter final in 2010.