It was 1976 when Jack Nicklaus founded the tournament at Muirfield Village Golf Club, an Ohio course he designed. The legendary golfer said he still remembers the nerves he felt that first year.
"Well, back in those days I was pretty much chief cook and bottle washer," he told reporters this week. "I sort of was involved in everything."
Roger Maltbie won the inaugural event in a playoff against Hale Irwin. A somewhat distracted Nicklaus finished four strokes back in eighth place.
The host recalled that by the end of each round, his caddie would be loaded down with crumpled paper and cigarette butts.
"Anything I found on the golf course I picked up and we put in his pocket," Nicklaus said. "And I just wanted to have a clean golf course."
On Thursday, Casey stood at four-under through the first 12 holes.