Five-time Major victor Phil Mickelson was among a group of six players tied for third place on six under which also included Australia's Jason Day.
Mickelson trailed American leaders Brian Gay and Scott Langley, who also played at Monterey, by one stroke.
The last time he hit every fairway in a PGA Tour event was at Torrey Pines back in 1998, according to the Tour. 'I may have done it before but I don't ever recall doing it'.
"It's about how do I improve to get myself into contention this week and then what do I do next week and just staying very present and recognising the longevity of a career", Spieth said.More news: Tesla cuts Model 3 price for second time this year Reuters
Mickelson is regarded as having arguably the greatest short game in golfing history but has perennially struggled with the driver.
Pebble Beach is a happy hunting ground for the 48-year-old, who has won the event four times.
Northern Irishman Graeme McDowell is four under after bogeying the final hole at Pebble Beach.
Most of the big names on Thursday were at Monterey, where Australian Jason Day matched Mickelson's 65, while Americans Dustin Johnson and Jordan Spieth fired 66.More news: Lavar Ball: Lakers' 'Luke Walton Was the Worst Coach Ever for Lonzo'
Big names in the field: Jason Day, two-time victor Dustin Johnson, 2017 champion Jordan Spieth, Phil Mickelson and Adam Scott.
He played Pebble Beach on Tuesday and will play one of the other two courses used for the tournament - Spyglass Hill or Monterey Peninsula Shore Course - on Wednesday.
"I'm not the first pro that has struggled on the back nine at Pebble, and won't be the last", said Gogel, 28 at the time.
Jordan Spieth has not lifted a trophy since the 2017 British Open and has drifted to 21st in the world rankings but the Texan says he would have had a good career even if he never wins again and that he will not go chasing results.More news: Unai Emery reveals Arsenal loanee Denis Suarez trained alone on Monday