Hewitt facing injury crisis

A persistent hip injury is threatening to derail Lleyton Hewitt's French Open and Wimbledon campaigns before they even begin.

The former world No.1 has been troubled by the injury since the end of the US hardcourt season last year and is awaiting the results of tests after undergoing treatment at a Sydney hospital on Tuesday.

The outcome of those tests later this week will determine when the Wimbledon and US Open champion can return to the circuit after a month on the sidelines.

"The hip is starting to feel a little better but I'm yet to fully test it out on court," Hewitt said.

"The specialist did a couple more tests today but the results won't be back for a few days. Once I get those I can make a decision on the French Open and the grasscourt season."

Ranked 19th in the world, Hewitt is in danger of slipping out of the top 20 for the first time since January 2000 and could even fall out of the top 40 if he is forced to sit out the entire clay and grasscourt campaigns.

The 27-year-old - who led Australia to a 5-0 whitewash over Thailand in the Davis Cup zonal tie in Townsville last month - reached the last 16 at Wimbledon and Roland Garros last season.

"He is doing everything in his power to compete in both Grand Slam tournaments (this year)," Hewitt's manager David Drysdale said.

"Grand Slams are well and truly the highlight of a tennis player's year, particularly an athlete as competitive as Lleyton. He hasn't given up on them, but is just frustrated that he can't be already out there competing and preparing."