Brett Quigley, Tom Pernice, Jr., Bo Van Pelt, Brent Geiberger and Brenden Pappas are knotted at 6-under-par 66.
Dufner's rookie season on the PGA Tour has been a rough one with several missed cuts, including each of his last three events. The 27-year-old is well outside the top-125 on the money list, but a good week can change anybody's fortunes.
'I don't really have anything to lose,' said Dufner. 'Doesn't matter if I finish 20th or eighth or 10th or anything like that. I need top-5s or better to secure my card for next year.'
Dufner ran off three birdies on the front nine and picked up steam on the inward half to move into the lead. He picked up back-to-back birdies starting at the par-3 12th and drained a 6-foot putt for a birdie at the 15th.
At the par-3 17th, Dufner dropped his tee shot inside 5 feet and rolled in the putt to secure the outright lead at Forest Oaks Country Club.
'I really don't have a thing to lose and so be it,' he said. 'If it works out and I end up playing well and into contention, with a chance to win, then I'll feel pretty good.'
Pappas is one of the many looking for a big week to assure himself of a spot on the PGA Tour in 2005. The South African is currently 134th on the money list.
'I have it in the back of my mind, especially when I'm off the course,' said Pappas. 'But once I'm on the course, you get involved in what you are doing there.'
Pappas got into the red quickly with an eagle at the par-5 second after his second shot stopped within 10 feet of the hole. He gave a shot back with a bogey at the fourth, but hit his tee shot to 16 feet for a birdie at the par-3 eighth.
The 34-year-old added a birdie at the ninth and moved to 4 under with a birdie at the 11th. Pappas landed his second shot from a bunker inside 2 feet for a birdie at the 14th and chipped in from off the green for a birdie at the par-5 15th to finish one shot off the pace.
'You can fire straight on at the hole. I think I remember last year the greens being a lot harder,' said Pappas. 'But the greens definitely have the potential to get rock hard. So depending upon what happens tomorrow, will determine what the course plays like for the weekend.'
Quigley, Pernice and Geiberger each posted bogey-free rounds of 66 to join the logjam in second place.
Van Pelt, currently ranked 40th on the money list and within reach of an exemption to the Tour Championship, played the back side first and collected four birdies over his first nine holes.
The 29-year-old then birdied the second, but found trouble with a bogey at the very next hole. Van Pelt recovered with a birdie at the sixth and tallied a birdie at the ninth for his share of second.
'That was something that was a goal I tried to set before the year started,' Van Pelt said of playing in the Tour Championship. 'I got a little too caught up in it thinking about it maybe the last six or seven weeks and even though I was playing well, I wasn't having much fun. This week I was just trying to have fun again.'
Justin Rose, Steve Elkington, Billy Andrade, Hank Kuehne, D.J. Brigman, Blaine McCallister, Jay Delsing, Bob Burns, Todd Fischer, Carl Pettersson, Dan Olsen and Richard S. Johnson share seventh place at 5-under-par 67.
Amateur star Ryan Moore, a senior at UNLV who won a slew of events this year including the U.S. Amateur and NCAA Individual Championship, finished in a group at 4-under-par 68 that features defending champion Shigeki Maruyama.