The new deal will keep the Germany Under-21 international at Freiburg until the summer of 2015.
Freiburg general manager Dirk Dufner told kicker-Sportmagazin: “We are proud to have been able to keep one of the most interesting young goalkeepers in Germany at our club.
“Oliver ties himself down to a deal with Freiburg because he is aware he has every opportunity to progress as a goalkeeper at our club.
“He is 100 per cent behind the club.”
