Last Updated: Sat, 30 Jan 2010 11:03
Phil Mickelson has been accused of cheating at Torrey Pines for using wedges that are only allowed under a legal technicality.
The PGA has banned the use of square grooves on irons this season in favour of V-shaped grooves, but back in 1990 club manufacturer Ping filed a lawsuit against the USGA protecting their clubs at the time- a fact not lost on several of the players in the Californian field.
The ruling states that any 'Ping-Eye 2' club made before April 1, 1990 remains approved for play on the tour because it takes precedence over any rule change.
At least four players are using the loophole to their advantage in San Diego this week and fellow professional Scott McCarron was incensed after hearing that Mickelson appeared to be trying to sidestep the rules, saying: "It's cheating, and I'm appalled Phil has put it in play."
Mickelson refused to get into a war of words with McCarron but did make it clear he is not a fan of the new rules imposed by the authorities this year.
"It's a terrible rule," he said. "To change something that has this kind of loophole is nuts. But it's not up to me or any other player to interpret what 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 - end of story."
On the course, 'Lefty' enjoyed a better second round and carded a five-under-par 67 on the North course at Torrey Pines to leave himself four shots off the halfway lead.
DA Points and Ryuji Imada share the lead on -11 while Englishman Justin Rose shot a 69 on the South course to take him to four under, with Martin Laird of Scotland on three under and Luke Donald two-under par after a level par 72.