LA JOLLA ---- The latest developments in the Farmers Insurance Open at Torrey Pines Golf Course did not leave Phil Mickelson feeling groovy.

Events on the golf course went smoothly enough, as Mickelson shot a 5-under-par 67 on the North Course for a 36-hole total of 7-under 137. That put him four strokes behind co-leaders Ryuji Imada and D.A. Points, who are deadlocked at 11-under 133.

But as Mickelson, 39, of Rancho Santa Fe, finished his round, he was quickly confronted with comments made by golfer Scott McCarron that implied he was cheating by using a Ping Eye 2 wedge that, while legal, has a design in violation of the new USGA rules governing clubhead grooves.

Although the Ping wedge has square grooves, which have since been outlawed by the USGA and PGA Tour, it is considered a "conforming" club because of the terms of a settlement of a lawsuit between the USGA and Ping dating to the early 1990s.

McCarron made the comments ---- "It's cheating and I'm appalled Phil has put it into play" ---- after the first round, and they appeared in a story in the San Francisco Chronicle. On Friday, McCarron backed off his comments a bit, saying he didn't intend to single Mickelson out.

"I don't feel this will be legal by the end of the year," McCarron told the Golf Channel.

Mickelson kicked off his season this week and, on Wednesday, when he met with the media for the first time, felt compelled to briefly address the personal problems of Tiger Woods as well as providing an update on the condition of his wife, Amy, who is battling breast cancer.

With just three of the top 20 players in the world rankings here this week, and all the tabloid attention surrounding Woods ---- the No. 1 player, if not the most famous athlete on the planet, who has not appeared in public since the car accident two months ago that kick-started the scandal ---- off-the-course issues have overshadowed anything happening between the ropes.

"It's a terrible rule," Mickelson said. "But it's not up to me or any other player to interpret what the interpretation of the rule is or the spirit of the rule. I understand black and white. And I think that myself or any other player is allowed to play those clubs because they're approved."

McCarron is a member of the PGA Tour Player Advisory Committee, which meets next week and will surely take up the matter of the groove debate and the Ping Eye 2 wedge.

In the meantime, a golf tournament is still going on and, heading into the weekend, it's clearly up for grabs.

Co-leaders Imada and Points have one tour victory between them ---- Imada's victory at the 2008 AT&T Classic in Atlanta. Imada made a nice run at this tournament in 2008, when it was called the Buick Invitational and he finished second to Woods. But even he had to admit he was playing for second that day, as Woods was 8 strokes clear of the field entering the final round.

This week, Imada has been a model of consistency. He hit 32 of 36 greens the first two days and has yet to record a bogey.

"My irons have been really good," Imada said. "I've hit a lot of greens and my putts from longer distance have been really good as far as the distance ---- judging the distances."

Imada opened with a 65 on the North Course and followed it Friday with a 4-under 68 at the longer, tougher South Course. Points played the same rounds in reverse, an opening 68 on the North Course followed by a 7-under 65 on the South. He has made only one bogey so far.

"I've played this course (South) a lot more than I've played the other one," Points said, "and I feel pretty comfortable out there. The main thing for this course is obviously just making putts and driving the fairway, and those are two things that I've done the last two rounds."

First-round leader Scott Piercy ran into trouble on the South after a 64 on Thursday on the North. He had three bogeys, one double bogey and no birdies, although he did register an eagle on the sixth hole (his 15th, because he started on the back nine), and pumped his fists in the air, largely in relief, when his 6-foot putt dropped.

Michael Sim shot the low round of the day, a 10-under 62 on the North with an eagle on the final hole, leaving him at 9-under 135 and tied with tour rookie Matt Every for third place.