Jason Bohn carded an impressive round-of-61 on Saturday to catapult himself into contention for the Greenbrier Classic in West Virgina.
The 42-year-old holed 10 birdies in a nine-under-par round to finish on 11 under for the tournament - level with co-leaders Sean O'Hair, Bryce Molder and S.J Park.
Chad Collins, Danny Lee, Justin Thomas and David Hearn are among those in pursuit as the quartet sit one stroke back on 10 under.
Meanwhile, Tiger Woods yet again failed to build on his promising opening-round 66 by carding 71 to finish seven shots off the pace.
Elsewhere, England's Greg Owen is three strokes behind on after carding 70 - five shots worse than his 65 on Thursday.