"He's off the court completely for two weeks, and the plan at this point is to pull out of everything in February, so he's pulling out of Marseilles and Dubai," Larkham said. "The doctor really thinks it will be 4-6 weeks, so if it's four weeks it means he could play Davis Cup, if it's six he might not be able to.

"So we're really just playing it by ear, see how the next few weeks go, and assess how it progresses. We don't know how quickly it's going to heal. The doctor just said 'I just can't tell you if you're going to be able to play Davis Cup or not… You're not going to know until the week before, really, whether it's going to be all right'."

He was not quite right during the Australian Open, which makes the exciting youngster's demanding passage to the last eight via two four-set and two five-set matches even more meritorious. "He had the cortisone (injections) back in December, just before Christmas, but he didn't take pain-killers, he just played through it," Larkham said.

"It was obviously very gutsy, and he was in a lot of pain, but he just wanted to play the tournament, and wanted to do well, so it was a pretty damn good effort, I think, making the quarters with a bone stress injury in your back."

After the resignation of Pat Rafter last week, Australia will be led by interim captain Wally Masur in Ostrava, with the squad likely to include Tomic, Lleyton Hewitt, Sam Groth and Thanasi Kokkinakis. The tie will be played on an indoor hardcourt, without Czech No.1 Tomas Berdych, a mainstay of the title-winning team in 2012 and 2013.