BEIJING — Liu Xiang's coach is doubtful the former Olympic champion hurdler will recover from surgery in time to defend his title at the world championships in Berlin in August.

The 2004 Athens gold medalist recently resumed training after undergoing surgery on his right foot in December.

The injury kept him from defending his 110-meter hurdles title at last summer's Beijing Games, where he sensationally withdrew at the start line in the heats. He was China's best hope to win gold in athletics at Beijing.

Liu's longtime coach, Sun Haiping, was quoted as saying in Monday's China Daily newspaper that August might be too early Liu to return to competition.

A September or October return "is a better choice," Sun said.

"He trains every day at present, but still cannot take on special training for striding hurdles," Sun said. "We don't want to put him at risk again."

Sun had earlier predicted that Liu might compete at worlds if he's able to run the 110-meter hurdles in under 13.20 seconds.

Liu, 25, set a world record of 12.88 seconds in 2005. That was surpassed on June 12 by Cuba's Dayron Robles (12.87), who won gold in Beijing.

Despite his Olympic disappointment, Liu remains hugely popular in China and continues to be a marketing dynamo.

Organizers of a distance running promotion in Beijing on Sunday had to cut Liu's appearance short after he was mobbed by fans seeking photos and autographs.

In earlier comments in his hometown of Shanghai, Liu said he was wearing extra soft shoes and socks to protect his foot during training.