He is happy to report, though, that he's hung onto his Malaysian tour card. In fact, in May he tied for 15th in the Malaysian PGA Championship; his pro-tour scoring average is around 73. "Just being a professional athlete is a thrill for an old guy like me," he says. Although Sheftall's U.S. Golf Association handicap is an impressive +4, meaning he'll beat a golfer with a -4 handicap by at least eight strokes, he fell out of the USGA's good graces after pointing out a mathematical flaw in its equivalency formula. He's since filed a provisional patent application for his own formula.

The USGA may not appreciate Sheftall's facility with math, but his physics acumen comes in handy on the course. For instance, he knows it's easier to putt straight downhill than uphill "because gravity vectors are always pushing the offline shots back online."

Sheftall intends to move back to the United States one day, and now that he's over 50, he could try to qualify for the U.S. Champions Tour. But he's not in any hurry. "I'm not going to do charity work forever, but right now I'm not ready to give it up," he says. "And I'm not just going to quit medicine and play golf--although I might do a little better as a golfer if I did."