The long hitting Beljan, second to only Bubba Watson in driving distance on the PGA Tour in 2012, is currently in 139th position on the money list and likely needs a top three this week to play his way inside the top 125 who will earn their playing rights for 2013.
Beljan leads by three shots over a group of seven players which includes Ryuji Imada, Harris English, Charlie Wi, Charles Howell, Mark Anderson, Henrik Stenson and the leading Australian Matt Jones.
Beljan was loaded into an ambulance via stretcher after completing Friday's second round of the Children's Miracle Network Hospitals Classic, battling shortness of breath and an elevated heart rate.
Beljan, who was expected to be taken to a local hospital, had to stop and sit down to rest several times during his round. He courageously fought through for a 8-under 64 at The Palm Course to take a 3-shot lead.
The 28-year-old Beljan is 12 under through 36 holes and is projected to move from 139th to 65th on the money list, which would secure his PGA TOUR card for next year. There was no immediate word on his status for the final two rounds.
Medical personnel walked with him for much of his back nine.
"A couple times I thought he might pass out," Adcox said Beljan's caddie Rick Adcox . "He just said, "˜I'm gonna keep going until I pass out or they take me off,' and I kept saying it doesn't matter to me, it's only a golf tournament."
Sydney's Matt Jones needs a big weekend if he is to avoid a visit to Tour School altogether. He is currently in 177th position on the money list and in order for him to avoid Stage Two qualifying he would need to finish inside the top three.
"I finally made some putts," said Jones after his round of 64. "First time this year, it feels like. So it was a good time to do it. Better late than never, so hopefully we can keep going."
"Yeah. If I putted how I do normally, I wouldn't be in this situation right now. So that's the only thing that's been a bit different this year. And that's what's pressuring other parts of your game so then you try to press in different areas. No. I didn't hit it well yesterday but spoke to my coach and figured some things out and hit it really well today."
The next best of the Australians at the halfway stage are Gavin Coles, Nick O'Hern and Stuart Appleby who share 57th place this week.
Mathew Goggin and Nathan Green are 70th and appear headed to Stage Two qualifying next week.
Rod Pampling, Robert Allenby and Steve Bowditch have missed the cut.