The New South Wales right-hander has spent the past fortnight having treatment on a sore hip, which forced him home early from last month's Chappell-Hadlee one-day series in New Zealand.
"I've had a couple of batting sessions and I haven't been getting anywhere near as much pain, I should say," Clarke told The Daily Telegraph.
"So I'm feeling good. Fingers crossed. But I haven't done too much running, so I'll have to do a bit of running over the next couple of days and see how it pulls up. But I'm pretty confident it's going to be fine."
Clarke is crucial to Australia's plans, particularly as the world champions, on a five-match losing streak, will be without all-rounder Andrew Symonds (torn bicep) for the first month and most likely opener Matthew Hayden (broken toe) for the two practice matches in St Vincent in the Caribbean.
Clarke, 25, plays a key role at number four, where his responsibilities will range from steadying the side after the loss of early wickets to maintaining a high tempo if Australia unleashes an early offensive.
His form was patchy through the home tri-series against England and New Zealand, and a more consistent campaign will be needed on the slow Caribbean pitches which could prove difficult for strokeplay.
Clarke knows what to expect of local conditions having made 170 runs at an average of 85 in four innings in an impressive series here in 2003.
"It's the number one stage for one-day cricket. That gives every individual an opportunity to step up on such a big stage," Clarke said of the World Cup.
"Hopefully, I'll get the chance to stay batting at four and there'll be plenty of opportunity to get out there and score some runs.
"So I'll be working my backside off over the next couple of weeks to make sure I'm ready to go for the first game."
Clarke averages 42.54 in 101 one-day internationals with two centuries and a scoring rate of 81.58.