In 2017, Díaz lost in a playoff to Ethan Tracy at the Club Colombia Championship. The finish moved him from outside the top 700 in the Official World Golf Ranking to 462nd, which qualified him for the WGC-Mexico Championship by being the highest-ranked Mexican golfer. Díaz also qualified for the U.S. Open, his first major championship, when Phil Mickelson withdrew to attend his daughter's high school graduation. He would go on to shoot 72-76 to miss the cut. Diaz finished 25th in the 2017 Web.com Tour rankings, the last guaranteed position for a PGA Tour card.