'It will be good exposure for them,' Williams said Tuesday. 'And it's good to be associated with a company that is synonymous with racing.'
That begs the question: Is he a caddie who races cars on the side, or a racecar driver who moonlights as a caddie?
'I treat each of them seriously,' Williams said Tuesday. 'I love to caddie and I love to race cars, and I give each of them my undivided attention when I'm doing them.'
He said Woods and Nike signed off on the deal, and he will continue to wear Nike hats.
Williams races 'saloon' cars, which he described as late-model cars on dirt tracks. He won three major races during his two-month break while Woods recovered from knee surgery, but he is ineligible for the season points race.
'You have to be there every week for that,' Williams said. 'I have two cars in two classes, so I just pick the best races.'
Williams started caddying for Woods at Bay Hill in 1999, and has been on the bag for 31 of his 41 victories worldwide, including seven of his eight majors.