Arron Oberholser, this year's winner at Pebble Beach, was tied for the lead with Ames as he moved to the 17th tee, but he found water and made triple-bogey -- and then drove into more water at 18 and made double-bogey. He lost five shots, and when Ames birdied 16, Oberholser fell six off the lead.
Former Masters champion Mike Weir, who holed his approach for an eagle at four, shared honors for lowest round of the day with a 4-under 68. He is tied for fourth at 210 with Henrik Stenson, who aced the 13th hole Saturday.
Tiger Woods, the 2001 Players Champion, mixed five bogeys and four birdies for a 73. The reigning Masters and British Open champion is tied for 23rd place at 2-under 214 -- seven shots off the lead.