OLDENBURG, Germany — Wladimir Klitschko's planned defense of his IBF heavyweight title against Alexander Povetkin of Russia on Dec. 13 in Mannheim, Germany has fallen through because of an injury to the challenger.

Povetkin damaged ligaments in his left ankle in training and will not be able to practice until the end of November, according to Heiko Mallwitz, a spokesman for Sauerland Promotions.

Povetkin, who is undefeated in 16 fights with 12 knockouts, was the mandatory IBF challenger.

Klitschko has a 51-3 record. The Ukrainian also holds the WBO and IBO heavyweight titles.

His older brother, Vitali Klitschko, beat Samuel Peter earlier this month to win the WBC heavyweight title.