Updated

Wolfsburg and Germany midfielder Thomas Hitzlsperger will undergo knee surgery Friday, but it was unknown how long he will be sidelined until after the operation.

Hitzlsperger, 29, has made five appearances for Wolfsburg, which he joined in the summer from English side West Ham. He started his career with Aston Villa, and has also played at Stuttgart and Lazio.

A member of Germany's 2006 World Cup team, Hitzlsperger earned regular playing time for his country over the next four years, but did not earn a spot on the 2010 World Cup squad.