Padraig Harrington, who always seems to be tinkering with his swing, attributes his victory drought to the change away from square grooves that began in 2010.
"I have been trying to deal with that for a few years now, and it makes a big difference to my game, no doubt about it," said Harrington, whose last official win was the Iskandar Johor Open on the Asian Tour at the end of the 2010 season.
Harrington said when the square (or box) grooves were allowed, he often had a mixed bag of clubs depending on the course conditions.
"I used to carry two sets of clubs to every event. I don't think anybody else did that," Harrington said at last week's Phoenix Open. "Depending on the length of the rough, sometimes you want the ball to come out spinning, sometimes you want the flier."
He said he used the V-grooves (less spin) at the U.S. Open because of the rough. And here's another calculation -- if a course had trees lining the fairways, he would not use the square grooves because the ball tended to come out lower and could not get over the trees.
"I might have a box-groove 7-iron, a V-groove 8-iron, box-groove 9-iron, all sorts of different combinations," he said. "That changes."
The most difficult part for Harrington has been with pitch shots. He said he has struggled to find consistency with the required V-grooves.
"With the old grooves, everything came out low and spinning," he said. "So it was a big advantage to me to be able to work it like that."
The Associated Press contributed to this report.