Following the 2019 U.S. Open, Day was being caddied by Tiger Woods' former caddie, Steve Williams. In June 2019, golf media reported that Williams was "the boss" of the player-caddie relationship and was telling Day what to do. "Pretty much when he asks you to do something you pretty much do it," Day said of Williams. Case in point: following an uninspiring round of even par on a rainy Thursday afternoon at the Travelers Championship, Day headed straight to the range at Williams' request. A day later, Day shot 63. "We've definitely been a lot more disciplined about going to the range and putting green, chipping green after the round and making sure we're staying on top of it, especially with our feels," said Day. "I've got a lot of work do . . . is very black and white." After Day missed the cut at The Northern Trust in August 2019, Day and Williams parted ways citing a 'disconnect between old school and new school'.