Once again, Mickelson is in contention after a layoff. He birdied seven of his final 10 holes, including each of his final four Friday at the Buick Challenge.
The lefthander finished with a 5-under 67 to enter the weekend at soggy Callaway Gardens Resort at 12-under-par 132.
Hes one shot back of Australian Craig Parry and overnight leader Tim Herron, both of whom used quick starts en route to earning a share of the 36-hole lead.
Parry birdied six of his first seven holes in round two in tying his career-best score on tour, an 8-under 64. Herron bogeyed his first hole, but then birdied five of his next six in shooting 68.
Rookie Jonathan Byrd is two back after a seven-birdie, one-bogey 66.
Mickelson has a new putter in the bag this week, but brought with him the same old aggressive game. He bogeyed the par-5 15th ' his sixth hole of the day ' when his 3-wood approach shot off a downhill lie finished in the greenside lake.
It really wasnt a hard shot. It was only 235 (yards) to the front of the green. I just hit it fat, Mickelson explained.
He then double bogeyed the par-4 17th after stubbing his chip shot and three-putting. But after a stern talking-to, he birdied three straight holes starting at the 18th, and closed with four more.
After the first six holes, being 2-over, I'll certainly take playing the last 10 in 7-under, he said.
Mickelson, who is making his first appearance in this event in 10 years, is vying for his third victory in 2002.
Parry would like to join the worlds No. 2 as a multiple winner this season. The 36-year broke a 235-event winless streak on tour at the NEC Invitational. Herron, on the other hand, hasnt won since the 1999 Bay Hill Invitational.
He went to the claw-style putting grip following last years Western Open and promptly tied for third at the Greater Milwaukee Open.
Ive been with it ever since, said Herron, who took 23 putts in round one and 28 in round two. What it does is it really gets my shoulders working and using my bigger muscles.
Muscles arent usually associated with the man nicknamed Lumpy, but they are with Parry, who is nicknamed Popeye due to his enormous forearms.
Parry started on the back nine Friday, and birdied 10 and 12-16, the last of which came courtesy of a 25-foot chip-in from a difficult lie.
'The ball kept going in from everywhere,' Parry said. 'Today was pretty special.'
The 6-under-par cutline at last weeks Disney Golf Classic was a new tour record. It was almost matched this week, as 70 players finished at 5-under-par or better. Defending champion Chris DiMarco missed the cut after rounds of 70-74. Last weeks winner, Bob Burns, will also have the weekend off after shooting 69-77.
Full-field scores from the Buick Challenge