Akshay Bhatia shot an eight-under-par 64 to share the second-round lead with Ryo Hisatsune at 15 under at the AT&T Pebble Beach Pro-Am.
Defending champion Rory McIlroy birdied the final hole to sign for a 67 but sits six strokes off the pace heading into the weekend.
The Northern Irishman made five birdies and an eagle but was left to rue bogeys on the 10th and 14th, although his four on the par-five 18th proved a more than satisfactory conclusion to the five-time major winner’s day.
American Bhatia had earlier produced one of the rounds of the day at Spyglass Hill, while Hisatsune recovered from dropping shots either side of the turn to pick up four shots in his final five holes.
Rickie Fowler was equally as impressive as he moved into a tie for second alongside Sam Burns, at 14 under as he chases his first win since July 2023.
Austria Sepp Straka is currently the best placed European player at 12 under, with England’s Matt Fitzpatrick two shots further back along with the likes of Keegan Bradley, Jordan Spieth and Xander Schauffele.
Englishman Tommy Fleetwood followed his 67 on Thursday with a 68 to sit at nine under with McIlroy, with Ireland’s Shane Lowry one shot further back.
A charging Scottie Scheffler brought himself back into picture with three birdies and an eagle on a five-hole stretch after the turn to reach the clubhouse at six under across the first two days.
England’s Justin Rose and Harry Hall are at five under with Scotland’s Robert MacIntyre, with each player in the field having played one round at Pebble Beach and Spyglass Hill.
All the third and fourth-round action will take place solely at Pebble Beach, with there also being no 36-hole cut at the $20m (£14.7m) PGA Tour signature event.