Brian Stuard carded a six-under 66 to be in a three-way tie for the lead after the third round of the Safeway Open.
Stuard jumped into a share of the lead at the Silverado Country Club in Napa, California after a fine round on Saturday.
The American produced a bogey-free round to be at 16 under alongside James Hahn (67) and Cameron Percy (68).
While Percy is aiming for a first PGA Tour title, Stuard and Hahn were last victorious in 2016.
Norway's Kristoffer Ventura (66), overnight leader Sam Burns (72) and Harry Higgs (70) are tied for fourth at 15 under.
Emiliano Grillo, who won the tournament in 2015, and Stewart Cink produced fine rounds to move into contention.
Grillo and Cink fired seven-under 65s to jump into 14 under and a tie for seventh alongside Doug Ghim (69), D.J. Trahan (70) and Russell Knox (70).
Phil Mickelson, meanwhile, slipped back into a tied for 43rd at eight under after shooting a 70.