Former Olympic and world 400m champion Jeremy Wariner has turned his attentions to London 2012 after being ruled out of the World Championships in South Korea.

27459 - Wariner out of Daegu after injury blow

Wariner is set to be on the sidelines for up to three months after tearing a ligament in the second toe on his left foot during training. The world's best 400m runner in 2010, Wariner has been plagued by a series of minor injuries this season.

"Right now my focus is to get healthy, prepare for next season, and try for my second 400m Olympic gold," he said.

Wariner, who won gold at Athens in 2004, claimed silver behind fellow American LaShawn Merritt at the 2008 Olympics in Beijing. The 2005 and 2007 world champion is expected to be replaced in the team by Jamaal Torrance in Daegu.