Wladimir Klitschko training to defend his mandatory WBO, WBA and IBF heavyweight world champion title against before he injured his hamstring. (Alexander Hassenstein/Bongarts/Getty Images)

Boxing fans will have to wait a few more months to see world heavyweight champion Wladimir Klitschko defend his WBO, WBA and IBF title against challenger Kubrat Pulev. Ukraine’s Klitschko, who is expecting a child with American actress Hayden Panettiere, injured his hamstring while training for the fight that was originally supposed to take place on Saturday night in Hamburg, Germany, ESPN reports. Klitschko’s promoter Tom Loeffler confirmed the news via Twitter.

Germany’s Bild magazine suggested the fight might occur at the end of October, but a new date will not be confirmed until a more precise schedule of Klitschko’s recovery time is known.

In the meantime, Klitschko’s opponent, Pulev, a 33-year-old from Bulgaria, will have more time to train following the two fights he’s been in to earn the No. 1 contender position for the title. Pulev, known as “The Cobra,” knocked out both his previous opponents in four rounds or less, ESPN reports.