By Jesse Reed

Jordan Spieth was using a new set of Titleist irons at The Barclays, and it showed.

This switch is likely the reason why he uncharacteristically missed the cut with a score of six over par (four strokes off the cut line) through two rounds, losing his No 1. overall ranking in the process.

It’s official: Jordan Spieth will miss the cut and lose his No. 1 world ranking after two weeks. As of Monday, Rory McIlroy is back on top. — Jason Sobel (@JasonSobelESPN) August 28, 2015

Spieth has been the hottest men’s golfer on the planet this season, and he came within a handful of strokes of pulling off a major championship sweep. Therefore it’s been surprising to see the 22-year old Texan struggle to hit greens this week at the Plainfield Country Club in Fairfield, N.J.

Perhaps now we know why.

According to PGA Tour equipment editor Jonathan Wall, Spieth is now using Titleist 716 AP2 irons this week, which is a “significant equipment change” for the now No. 2 golfer in the world.

Pretty significant equipment change for Jordan Spieth yesterday at The Barclays: added @Titleist's 716 AP2 irons. pic.twitter.com/8Q4zF22lUF — Jonathan Wall (@jonathanrwall) August 28, 2015

Before this change, Spieth had used the Titleist 714 AP2s all year long.

As for how much of a change these new clubs “should” be for the man favored to win Player of the Year in 2015, Golf.com’s Brendan Mohler doesn’t believe it would be significant. He also provided a bit of reasoning as to why Spieth would make this change now, at the start of the FedEx Cup playoff chase.

“Some may question why the current world No. 1 would make a switch at any moment during his spectacular season. But the change makes practical sense—Spieth can get a few weeks of competitive rounds under his belt with the new sticks, and completely break them in before 2016. Also, the Titleist 716 AP2 irons are likely only subtly different than the 714 AP2s.”

Regardless of what “should” happen, it does appear Spieth is struggling to get the hang of his new irons, hitting just 60 percent of greens in regulation at The Barclays. Unless he quickly gets the hang of the new feel, then Spieth could quickly find himself on the outside looking in for the remainder of the FedEx Cup playoffs.