Jim "Bones" Mackay will caddie for Justin Thomas on the PGA Tour in the 2021/2022 season, the famous carrier revealed to Golf Channel on Thursday.
Mackay had spent 25 fantastic years caddying for six-time major champion Phil Mickelson and together, they created some of the great moments in the history of the PGA Tour.
The 56-year-old has previously stepped in for Thomas' caddie Jimmy Johnson before, the first time being at the 2018 Sony Open when Johnson was injured.
Bones also stepped in when Johnson was injured during the WGC-FedEx St. Jude Invitational in 2020, which Thomas won by three strokes. Johnson has been caddying for Thomas since 2015.
"It came out of left field very recently. I have just tremendous respect for (Thomas) as a person and a player," Mackay told Golf Channel on Thursday.
"It was an incredible phone call to get and I said yes. I love to caddie and I loved my role with NBC/Golf Channel, but it’s Justin Thomas."
Mackay will continue to work for NBC and Golf Channel in his on-course reporting role, which he began in 2017, but only when the tour schedule allows him to.
Thomas, who won the 2017 PGA Championship and featured as part of America's record-breaking Ryder Cup team last week, has taken the week off away from the Sanderson Farms Championship this week.
This is an extremely unexpected but exciting announcement from Mackay and it will be great to see him back in the middle of the fairways on the PGA Tour.