Defending champion Grillo in uncharted waters at Colonial after course renovations

The course has undergone renovations since the 2023 edition of the event with new grass throughout, bunkers added and removed, and the elevation of some greens altered.

The 31-year-old Grillo was victorious a year ago at eight-under par, including a second-round 65, but has suffered a drop-off of form since with only five top-10 finishes since his victory there.

Ahead of the competition beginning in Fort Worth on Thursday, the Argentinian indicated he would proceed with caution on a much-changed course.

"New reads, new contours, new everything, so I've got to go out today and do my homework and pretend it's a place I've never played," he told the PGA Tour official website.

"(My form) isn't where I want it to be. I'm working really hard on it. I wish I could say different right now. The last month and a half or so it's been tough, but this is golf, everybody knows this.

"You can't always play good. When you don't, you just have to keep grinding, get through the storm, and enjoy the sunny days more than ever."

There have been significant changes to the course since last year. The revamped 13th hole for example now spans 199 yards, with the green elevated by 10 feet and moved further from the pond, and a large new tee box built creating more playing options.

"As long as the right tee box is played, I think it's a fantastic par three," said the 2016 champion Jordan Spieth.

"The firmness of the greens, it doesn't seem to me to be able to yield holding five-irons.

"But if it's a mid-iron in, a good shot gets really rewarded. Then if you miss in the wrong spot, you can be in big trouble."