South Korea's Hyeon Chung out of French Open

South Korea's Australian Open semi-finalist Hyeon Chung has pulled out of the French Open citing a long-standing ankle injury.

Chung, 21, announced the Roland Garros pullout in a tweet late yesterday, saying he had been forced to withdraw from a French Open warmup tournament in Lyon due to the injury.

"Unfortunately I had to withdraw from Lyon yesterday and now Roland Garros," he tweeted.

"I have been struggling with an ankle injury during the entire clay season." He said tests had revealed he had a build-up of fluid on the joint which might require "a small procedure" followed by rest.

"Thanks to everyone for all the support. Hope to see you soon and be back to full strength," Chung said.

Chung made a Grand Slam breakthrough when he reached the semi-finals of the Australian Open in January but had to retire in his match with Roger Federer because of a foot blister.