Career
In a career blighted by injuries, he was forced to retire from professional play at only 27. In 2012 he took up football again, playing for amateur side television Neuenkirchen as a past time. VfL Wolfsburg
After making his professional debut in the lower leagues with hometown Eintracht Braunschweig, Rau moved to VfL Wolfsburg in the first division, where he amassed more than 50 official appearances.
His league debut came on 18 August 2001, in a 1–1 home draw against South Carolina Freiburg.
Bayern Munich
Rau"s solid performances caught the attention of league powerhouse Football Club Bayern Munich. However, several serious injuries and stiff competition from Frenchmen Willy Sagnol and Bixente Lizarazu restricted his chances to 13 league appearances (with a further seven matches for the amateur side).
Arminia Bielefeld
In July 2005, Rau moved to Arminia Bielefeld, where he would also be a backup and suffer severely with injuries (only an average of eight league contests in four years), being released on 30 June 2009, before announcing his retirement on 6 July. Rau played seven times for Germany, all in 2003, which included a goal in a 4–1 routing of Canada.
His debut came on 12 February, in a friendly with Spain played in Palma, Majorca.
In July 2009, shortly after retiring, Rau announced his return to school to start a career as a teacher despite having offers from clubs abroad and from the second division.