Matteson clings to John Deere lead
Matteson's 13-under par total of 129 gave him a one-stroke lead over Jeff Maggert and Brian Harman.
Maggert climbed up the leaderboard with a bogey-free round of nine-under 62, matching his career-low round. He capped his effort with a 13-foot birdie putt at the ninth.
Harman notched his second straight 65 to join Maggert on 130.
"I saw the putts better today," Maggert said. "But I'm going to be aggressive tomorrow. I feel I need another really low round Saturday or Sunday, seven- or eight-under, to be in contention."
J.J. Henry (64), England's Gary Christian (66), Robert Garrigus (66) and Ricky Barnes (67) were tied on 131.
A trio of players on 10-under 132 included three-time defending champion Steve Stricker, who stayed within striking distance with a four-under 67.
"I like the spot I'm in," Stricker said. "I'd rather kind of be there at this point.
"I'm hitting better putts," Stricker said. "I feel my confidence coming back. I'm standing over putts thinking I've got a good opportunity to make them, even from 20 to 30 feet."
Matteson, a two-time winner on the US PGA Tour, launched his round with an 11-foot birdie putt at the first.
He two-putted for birdie on the par-five second.
He parred the next seven holes but picked up two more birdies at 10 and 14 before his lone miscue of the day at the par-four 15th.
"Greens were a lot smoother this morning," Matteson said. "They weren't a lot faster, but they were a little faster so we couldn't be as aggressive with some of the putts.
"The wind picked up for a few holes, so I know that changed the way a few guys played holes. I know holes like No. 5 played 40 yards longer."