WHITE SULPHUR SPRINGS, W.Va. - Tim Petrovic walked off the course Saturday after shooting a 3-under-par 67, his best round in four years of playing the Greenbrier Classic.It left him at 6 under for the tournament and tied for 16th heading into today's final round, almost assuring his biggest payday of the PGA Tour season.About the only thing that might have made it better was if younger brother Stephen was at his side.The last time out for Tim Petrovic, two weeks ago in the Travelers Championship in Cromwell, Conn., marked the return of Stephen as his caddie. Stephen Petrovic served in that role off and on from 1989-2009, and was on the bag for Tim's only PGA Tour win, the 2005 Zurich Classic in New Orleans.But making that event all the more special, aside from the fact that Stephen, 44, lives in nearby Farmington, Conn., was that it was the first time Stephen had caddied since being diagnosed with acute myeloid leukemia in January of 2012."He made it through four rounds,'' Tim Petrovic said. "That was a victory that week just to get him out there. Just to have guys come up to him and give him a little bump and say, 'Glad to have you out here.' It was good. We put that on the calendar just to kind of get him out there.''Following his diagnosis, Stephen Petrovic underwent radiation and chemotherapy, and had a stem cell transplant in May of 2012. He's taken as many as 17 oral medications per day and occasional booster shots.The leukemia is now in remission, although Stephen isn't ready to return to caddying chores on a weekly basis, and wasn't able to make the trip to The Greenbrier resort this week."He's got no restrictions from his doctors,'' Tim Petrovic said, "but he's still on 15 meds a day and still feels like crap. So it was tough for him [caddying two weeks ago]. You can tell he hasn't been outside a lot and he didn't have energy like he normally does. Normally, he's 20 yards ahead of me and this time he was 20 yards behind me. His ankles were really swollen when he was out there."We're playing it by ear right now. In years past he's done seven, eight, nine tournaments. He doesn't want to come out there every week, so he's going to come out now and then to help me out, which is good. It keeps it kind of fresh. He's a good brother. He's a great brother and a great caddie, too.''Tim Petrovic, who turns 47 in August, said it means a lot when Stephen walks the course with him."I just wanted to have him out there,'' Tim said. "He doesn't even have to caddie. I just want him to come out and walk around, so that was a bonus [last week]."I'm going to try to get him out there sometime the next few weeks and we can hang out. I don't know what his schedule is. He's starting to do some lawyering. He's got a little murder trial he's sitting in on.''Tim Petrovic is thankful he and his brother are united again, because it wasn't so long ago that they were estranged."We had an unfortunate thing,'' Tim said. "We had a little falling out a year and a half before [Stephen's diagnosis] and we didn't talk to each other for a year. I just patched things up with him six months before, and then that following winter, he finds out. So I'm glad we got things [worked out]."It's still a real shocker when you hear something like that. Because now I'm the guy always talking to the doctors and asking questions. [Stephen] doesn't want to know anything. I think he's scared to hear real answers. It's a 'No news is good news' kind of thing for him. The prognosis is good. It's highly treatable, but they don't know what causes it.''Perhaps the return of his brother as caddy in the last tournament helped boost Tim's game.Tim Petrovic, a Massachusetts native who now lives in Austin, Texas, made just his third cut in seven events at the Travelers Championship and a tie for 63rd gave him his biggest paycheck of the year ($12,871). His best finish is a tie for 50th at the Puerto Rico Open.This week, he's posted three straight sub-par rounds (69-68-67) and has now gone under par seven straight times at the par-70 Old White TPC. Saturday's round included five birdies and two bogeys.He stands to better his finish from last year - the first time he made the cut in three tries at the Greenbrier Classic - a tie for 38th at 5-under 275, which earned him $24,400."I'm working on trying to hit more fairways,'' Tim Petrovic said, "and more greens - more greens in particular. Get the putter in my hands. I was trying to keep a clean card [with no bogeys] and then get something going tomorrow, but I wasn't able to do that.''Reach Rick Ryan at 304-348-5175 or email@example.com.