Brenden Pappas posted a 67 to move into a share of second place at 9-under- par 135. He stands alongside David Mathis, who shot 68 in round two.
First-round co-leaders Matt Hendrix and Tim Wilkinson each posted rounds of 1-under 71 on Friday. They are joined in a share of fourth place by Jason Caron (67) and Brendon De Jonge (66).
Haas, whose lone tour win was here in 2004, opened his second round on the par-five first and quickly birdied that hole. He settled in to par the next five holes before a 20-foot birdie putt on No. 7 at Fox Den Country Club got him to minus-7.
The 28-year-old jumped up the leaderboard with an eagle at the par-5 10th after his approach stopped 2 feet from the cup. Haas came back with a birdie at 12 to move to 10 under.
Haas parred his next four holes. The native Texan chipped in for birdie on the 17th and he parred the last to end two clear of the field.
'I drove the ball really well. Driving is not as demanding as it has been here in the past, but you still want to get it out there as far as you can,' said Haas. 'I just want to keep plugging away and make as many birdies as I can.'
Pappas played the back nine first on Friday and got going with birdies on 10 and 12, moving him to minus-6. He birdied the par-5 18th, then eagled the par-five first to jump to 9 under.
The 38-year-old then birdied the second as well. Pappas however gave that stroke back as he bogeyed the par-5 sixth. He closed with four straight pars to end at minus-9.
'I've hit it beautifully the first two days,' Pappas admitted. 'I'm a little disappointed with my total. I'm not necessarily putting a bad stroke on it, but I'm reading the greens badly.'
Mathis, whose best finish on tour was a tie for 14th two weeks ago, got off to a flying start. He eagled the first, then came back with birdies on two and four to get to 9 under.
The 32-year-old slipped to a bogey on the par-four eighth. Mathis recovered that stroke with a birdie on No. 10, but closed with eight straight pars to remain in a share of second at minus-nine.
Richard Johnson (71), Joel Kribel (70), Parker McLachlin (70) and Michael Boyd (69) share eighth place at seven-under-par 137. Tom Johnson, Tim O'Neal, Michael Putnam and Boo Weekley are one stroke further back at minus-six.
The cut line fell at two-under-par 142 with 70 players moving on to the final two rounds. Among those who missed the cut were 2005 winner Kim Felton as well as former PGA Tour winners Bill Glasson and Notah Begay III.