Duplantis was in Del Mar when he stepped off a center median and into the path of a taxi, said Sgt. Randy Webb of the San Diego Sheriff's Department. The 35-year-old Duplantis was pronounced dead on the scene.
He was working at the Buick Invitational for Eric Axley.
Axley was visibly shaken when he arrived at Torrey Pines and asked for a few days before he commented.
Duplantis was a free spirit after hours who was regarded as among the best caddies inside the ropes. Jim Furyk won four times early in his career with Duplantis on the bag. The caddie also steered Rich Beem to his first PGA TOUR victory in the 1999 Kemper Open, and he was with Tommy Armour III when he set the PGA Tour's 72-hole scoring record at the Texas Open in 2003.
Among the nicknames caddies gave Duplantis was 'Asbestos,' because he was thought to be fireproof. Even though he often showed up late for work after a night on the town, his value as a caddie was too much for players to replace him.
'He was one of the better caddies,' Armour said. 'That's why he kept getting hired. He was very confident with what he said.'
Armour, however, feared Duplantis' nightlife would land him in trouble.
'Am I shocked by this? No,' Armour said. 'I tried several times to get him some help. And I told him in 2003, 'Bud, if you don't change, you're going to die a tragic death.'
Duplantis and his nightlife exploits were prominently featured in a book titled, 'Bud, Sweat and Tees,' a story primarily about Beem.
Beem and Duplantis were together only about six months, the first time at the 1999 Kemper Open, Beem's first TOUR victory.
Beem, who later won the PGA Championship at Hazeltine, was informed of his death during the pro-am.
'He was the first person who showed me the value of a good caddie, which I now have,' Beem said. 'You felt comfortable with him on the bag because he knew what to say. He was confident.'
Beem mostly remembered how Duplantis looked after his daughter, Sierra, who turned 12 this month. His marriage ended quickly, and at one point Duplantis was a single parent trying to keep his job as a caddie. He worked with Furyk for four years until he was fired for showing up late one time too many.
'He always lit up when talking about Sierra,' Beem said. 'He always had current pictures of her in his wallet. For a lot of years, he was the only parent in her life. Yes, he liked to party. But that part of his life gets lost.'
The mood was somber on the putting green, where some caddies were waiting on their players.
'He was a throwback,' caddie Patrick Smith said. 'He raised the level of every player he worked for. He could take guys who were marginal and they would play well.'