Career
After failing to find a contract for 2013, Gerdemann joined MTN–Qhubeka for the 2014 season. As of 2015 he rides for Danish professional continental team Cult Energy-Vital Water. After riding on amateur teams Team Winfix and Team AKUD Arnolds Sicherheit, in 2005 he became a professional rider for Team Civil Service Commission after a recommendation from Dennis Kraft, signing on for a 2-year contract.
In late 2005 he agreed to a contract with rival UCI ProTour T-Mobile Team, starting from 2006.
This got Team Civil Service Commission owner Bjarne Riis to release Gerdemann from his contract at the end of 2005. On Saturday 14 July 2007 he secured his biggest victory to date, the seventh stage of the Tour de France from Bourg-en-Bresse to Le Grand-Bornand.
He was also awarded the combativity award for this stage. In March 2008 he sustained injuries from a crash in the Tirreno–Adriatico and was unable to race in the 2008 Tour de France or the Beijing summer Olympics.