Sang-Moon Bae and Fredrik Jacobson both carded 6-under 65s on Friday to snare a share of the lead after two rounds of the Northern Trust Open.
Bae and Jacobson sit at 9-under 133 through 36 holes, one stroke ahead of John Merrick and John Rollins, who shot 66 and 65, respectively.
World No. 3 Luke Donald fired a 66 to move into sole possession of fifth place at 7-under, while Charl Schwartzel (67), Webb Simpson (66) and Lee Westwood (68) are tied for sixth at minus-6.
Donald and the 2011 Masters Champion Schwartzel are both making their PGA Tour season debuts. The former hasn't played since the European Tour's DP World Tour Championship in November, while the latter has already produced a win and a second-place finish overseas.
"You never know with how you're going to deal with being back in competition again, but certainly a big improvement today, ball-striking wise and my short game has been very sharp," said Donald. "I've been excited about that. It's been a big key to my score so far, and, yeah, excited to be in the mix again."
Matt Kuchar held the lead on Thursday when play at Riviera Country Club was suspended due to fog. He was still on top when the first round concluded Friday morning, but he suffered a pair of double-bogeys early in his second round and never fully recovered, ending with a 73, which dropped him into a tie for ninth place at 5-under.
Defending champion Bill Haas (67), John Mallinger (66) and Ryan Moore (67) also sit at minus-5 through 36 holes.
Phil Mickelson, who, along with Keegan Bradley, lost to Haas in a playoff last year, carded a 67 and moved into a tie for 13th at 4-under. Adam Scott (67), the 2005 champion at this event, Sergio Garcia (73) and Ernie Els (68) are also 4-under. Garcia was one shot off Kuchar's pace at the conclusion of the first round.
Graeme McDowell, also making his season debut, Dustin Johnson, Zach Johnson and Bubba Watson were among those that missed Friday's cut.
Bae, a second-year player from South Korea, is seeking his first PGA Tour victory after producing a pair of top-10 finishes last year. He began his second round on the 10th tee and got off to a roaring start with four straight birdies to catch the idle Kuchar at 7-under.
An up-and-down finish followed for Bae, who bogeyed the par-4 15th before closing his outward nine with a birdie to stay at minus-7. Around the turn, the 26-year-old reeled off three birdies in four holes to grab the outright lead at 10-under. He then sandwiched a pair of bogeys around a birdie before closing with consecutive pars to hit the clubhouse at 9-under.
Jacobson, looking to improve on last week's tie for seventh at Pebble Beach, began on the first tee and quickly set about catching the clubhouse leader. He birdied his first two holes and highlighted his bogey-free outward nine with two more birdies -- at Nos. 5 and 9 -- to make the turn at 7-under.
He began his inward nine in similar fashion, picking up back-to-back birdies to catch Bae at 9-under. After a par, Jacobson found himself in sole possession of the lead when he birdied No. 13, but a bogey on the 15th dropped him back into a share of the top spot.
"Obviously take a lot out of that, just being in contention again," noted Jacobson. "I've had some good practice sessions before, but to bring it on the course and play under pressure, that's what it's about. And the sooner I can get back and put myself in this position where I can get some pressure, that's the best practice you can get."
NOTES: Jacobson is seeking his second PGA Tour win. He titled at the Travelers Championship in 2011 ... Last year, Bae tied for fifth at the World Golf Championships - Accenture Match Play Championship and lost in a playoff at the Transitions Championship ... Schwartzel won the SA Open Championship and placed second at the Joburg Open this season on the European Tour ... Scott is making his season debut.