Jordan Spieth makes a putt and Justin Thomas appeals to the crowd for some cheers. (0:24).
Justin Thomas lured Jim "Bones'' Mackay from his broadcasting job to become his full-time caddie.
Sixth-ranked player in the world, Thomas won the Players Championship in March. He was also a member of the victorious U.S. Ryder Cup.
Mackay will continue to work on a limited basis for Golf Channel.
Mackay said that the idea came out of nowhere recently. I have immense respect for him as both a person, and as a player. It was an amazing phone call and I agreed.
"I love caddie, and I loved my role on NBC/Golf Channel. But it's Justin Thomas."
Justin Thomas was the winner of the WGC/FedEx St. Jude Invitational 2020. He was accompanied by Jim "Bones' Mackay, his caddie. Mackay, who caddied Phil Mickelson for 25+ years, before becoming an analyst at NBC Sports and Golf Channels, will now be Thomas' full-time caddie. EPA/Tannen Maury
Last year, Mackay was Johnson's substitute on two occasions, one for a win at the WGC–FedEx St. Jude Invitational, and the second week at the PGA Championship.
Mackay was a caddie for Phil Mickelson from the summer of 1975 to 2017, before he joined NBC/Golf Channel's on-course reporting team.
Johnson was earlier this year inducted into Caddie Hall of Fame during the BMW Championship. Thomas was his previous employer, Nick Price and Steve Stricker. He also played professional golf on the South African Tour.