Phil Mickelson hits out of the rough on the first hole hole during the final round of the 2010 Farmers Insurance Open. AFP photo

Padraig Harrington is prepared to exploit a loophole in new rules governing clubface grooves, but the Irish golfer, like his colleagues, would like to see some clarification of the contentious issue.
Harrington said Tuesday he has tested a Ping-Eye 2 wedge, a 20-year-old club that doesn't conform to the new rules for this season, but which remains approved for play in the United States thanks to the settlement of a lawsuit between Ping and the U.S. Golf Association in 1993.
Harrington said the wedge offers a "significant difference" in his ability to control distance out of the rough. "What I'm doing is preparing myself for all eventualities. It would be naive not to," Harrington said.
But players learned at a meeting at Riviera Country Club on Tuesday that a resolution to the problem could take some time.
The new rules adopted by the USGA and the Royal and Ancient this year mandate smaller "V-grooves" rather than square or "U-grooves," which generate more spin.
The issue became a hot topic during the Farmers Insurance Open at Torrey Pines last week, where world number two Phil Mickelson was among a handful of players to use a Ping-Eye 2.
Fellow pro Scott McCarron told the San Francisco Chronicle he thought use of the club was "cheating."
"It's cheating, and I'm appalled Phil has put it in play," McCarron told the newspaper, a comment that prompted a miffed Mickelson to say he had been "publicly slandered."
On Tuesday, McCarron apologized for the tone the debate had taken, and to Mickelson personally.
Although he disagrees with the current rule, McCarron said, "I'm sorry I singled out any player."
Mickelson, also a harsh critic of the rule as it stands, has noted that the Ping club was approved for play, and said players shouldn't be called on to interpret the spirit of the rules.
Harrington agreed. "I think most of us were brought up that you've got to adhere strictly to the rules," Harrington said, noting that sometimes the rules worked out to a player's benefit and sometimes to his disadvantage.
"You have to play exactly by them ... the interpretation of them, that leads to problems, and has led to problems over the years. So that's why we stick by it."
Steve Stricker, who was runner-up to Mickelson at Riviera last year, said the rule "isn't very good."
"I didn't care for (McCarron's) words, with using those two words so closely together - 'cheating' and 'Phil Mickelson,'" Stricker said.
"We have enough going on in our sport right now where we don't need any more attention to something like this."
The USPGA Tour said in a statement last week that the Ping-Eye 2s are permitted for play, and it was "inappropriate" to characterize their use as a violation of the Rules of Golf.
"We don't want the public to think people are out here breaking the rules," American Stewart Cink said.
However, Cink said players were told that the PGA Tour doesn't have the power to unilaterally ban the Ping-Eye 2s. Instead there is a legal process laid out in the lawsuit settlement that must be followed.
In addition, the manufacturer could intercede.
Ping chief executive John Solheim said in a statement that the company expects the tour to honor the settlement, but added: "I'm willing to discuss a workable solution to this matter that would benefit the game and respect the role innovation has played over the long history of golf."
McCarron said players had been told Tour officials had a simple reason for failing to close the loophole before the new rules took effect.
"They didn't believe players were going to play a 20-year-old club," he said.