Jordan Spieth isn't one to tinker with his gear—especially mid-season. So when the three-time major winner showed up at this week's Cadillac Championship with a noticeably revamped setup, the golf world took notice. And after firing a first-round 65—his best score of the season and just one shot off the lead—it's clear the changes are already paying off.

So what exactly did Spieth change? In an "extremely rare" in-season equipment overhaul, he debuted a new Titleist GTS2 driver and 3-wood, and perhaps most notably, switched to the Titleist Pro V1x Left Dash golf ball. For a player who has relied on the standard Pro V1x for most of his career—a ball known for higher spin, especially with irons and around the greens—this is a significant move.

Why the switch? Spieth admitted he's been battling excess spin for the past year and a half. "I've been spinning a lot... I just thought it was a driving range thing," he explained after his round. But after taking a launch monitor onto the course, he noticed something troubling: "Maybe a dozen shots in the last year that came off odd for an iron, spinny, ended up short."

The Left Dash is designed to produce lower spin, especially with the driver and longer irons, giving Spieth a more penetrating ball flight and tighter distance control. He had hoped to test it at the Masters, but Augusta National's no-launch-monitor policy forced him to wait until the RBC Heritage the following week. Once he confirmed the results, the switch was on.

For Spieth, who has always valued feel and consistency, this kind of mid-season change is almost unheard of. But with the season heating up and a major championship window opening, it seems the three-time major champion is willing to step outside his comfort zone in pursuit of an edge. And if Thursday's 65 is any indication, the new gear might just be the spark he's been looking for.