Four players are tied for the lead going into the final round of the Humana Challenge in California.
American Ryder Cup star Matt Kuchar had looked poised to preserve his narrow lead as he was four-under par for his round through 15 holes.
However, the world number 11 bogeyed three of the final four holes to end up one stroke off the pace set by Bill Haas, Erik Compton, Michael Putnam and Justin Thomas on 17 under.
Kuchar is in a four-way tie for fifth place alongside Ryan Palmer, who was unable to replicate his blistering form from round two.
Palmer followed his second-round 61 with a steady 68 to remain in the hunt.
