Poston had a 13-under 131 total at rain-soaked Keene Trace in the tournament where players are allowed to use preferred lies in the fairways because of the wet conditions.

"It's been really good," Poston said. "Just ball-striking's been a lot better than I'd say it has been the last few months. Just nice to give myself a lot of looks.

"They're bent greens, it's soft. Hit the ball close to the hole and you can make a few putts, too."

Poston had late birdies on the par-4 seventh and par-5 eighth in the round that began on No. 10. The 28-year-old former Western Carolina player won the 2019 Wyndham Championship in Greensboro for his lone PGA Tour title.

Ryan Armour and Joseph Bramlett are a stroke back, each shooting 67.

"It was softer today," Armour said. "Definitely that rain yesterday afternoon, the two rain delays we had, I was not getting any bounce on the driver, it was kind of hit and plug, which I would love it if it would bounce a little more, the length I hit it, but I'm still able to get to three of the par 5s, which is good for me."

Brian Stuard, tied for the first-round lead after a 64, shot a 69 to drop into a tie for fourth at 11 under with Taylor Pendrith (68), Luke List (68) and Seamus Power (68).

"Today, obviously, wasn't quite as good," Stuard said. "I didn't think I hit my irons as well as I did yesterday, but hung in there nicely and was able to kind of put together a good score, which is good."

Defending champion Jim Herman was seven under after a 70. He won in 2019, and the event was cancelled last year.

Cameron Percy (69) and Greg Chalmers (71) are five and six shots behind the leader.

They are the only two Australians to make the four-under cut.