Phil Mickelson’s Caddie Jim ”Bones” Mackay

Sports Illustrated senior writer and golf expert Alan Shipnuck sits down with veteran caddie Jim "Bones" Mackay, who has carried the bags for Phil Mickelson for over 20 years, to discuss the new Jordan Spieth era and what it means for golf, and what it's really like to be side-by-side with Lefty on the green.