Melbourne: The Australian Open 2011 winner Kim Clijsters has been cleared of major damage to her hip and expressed guarded optimism on Saturday about recovering in time for the defence of her Australian Open title.

Clijsters, who beat China's Li Na to win at Melbourne Park last year, retired hurt during her semi-final against Daniela Hantuchova at the Brisbane International on Friday, complaining of tightness in her hip.

An MRI scan had diagnosed a muscle spasm on Clijsters's tensor fascia lata, a muscle on the outside of the hip, a report on the Australian Open website said on Saturday.

"With this one I kind of have an okay feeling," the report quoted the four-times grand slam champion as saying.

"If everything comes out okay it should take a little (less than) a week to get completely healed.

"I felt my left hip was getting tighter and tighter to the point I couldn't move forward with my upper body.

"The smartest choice was not to let it get any worse and try to be right for Melbourne."

Clijsters would have intensive treatment over the next few days and have a second check-up on Wednesday, the report said.

Her fellow former world number one Serena Williams, another player to pull out of the Brisbane tournament injured, has had her leadup to the year's first grand slam disrupted with a twisted ankle, but arrived in Melbourne on Saturday.

"I'm doing everything to heal up," Williams said on her Twitter account with a picture of her next to a private jet with her entourage.

In the men's draw, Roger Federer remains under a cloud after pulling out of the Qatar Open with a back injury following a grinding quarter-final win over Andreas Seppi, but said he was optimistic of proving his fitness in time for Melbourne Park.