Dustin Johnson birdied the 18th hole Friday to grab the second-round lead at The Northern Trust, the first stop of the PGA Tour's postseason.
Johnson hit his approach within 8 feet on the final hole and rolled in his fifth birdie of the day for a round of 4-under 67 and a total of 12-under 130 at rain-softened Liberty National Golf Club in Jersey City, N.J.
"All day today was solid," said Johnson, who opened Friday with a bogey.
"I felt like I gave myself a lot of chances and very makeable putts all day. Felt like I was rolling it good, too. I was burning the edges all day but hitting my putts with good speed. I did stay patient and I knew I was hitting it good, so I was going to keep giving myself chances."
He is one stroke up on Jordan Spieth (64 on Friday) while four golfers -- first-round leader Troy Merritt (70), Patrick Reed (66), Mexico's Abraham Ancer (65) and Spain's Jon Rahm (68) -- are lurking at 10 under.
Spieth, the former world No. 1, is looking for his first victory since the Open Championship in July 2017. He entered the week at No. 69 in the FedEx Cup standings, on the bubble to advance with the top 70 players to the second playoff event, next week's BMW Championship at Medinah Country Club near Chicago.
"I think that the turnaround in ball-striking week to week is certainly awesome to see that it's possible ... that it was close," Spieth said after a 7-under round that matched Andrew Putnam for the best score of the day.
"Historically, I'm a very consistent player. I've lost a bit of that. I still have the firepower, but that consistency is what I'm trying to get back. ... I'm in position, and there's going to be times where I'm out of position over the weekend. It's about limiting the mistakes."
Putnam was in a group of five golfers tied for seventh at 9 under. The others were Wyndham Clark (66), Englishman Justin Rose (68), South African Louis Oosthuizen (65) and Northern Ireland's Rory McIlroy (68) -- although McIlroy didn't know his place on the leaderboard until after his round.
He had incurred a two-stroke penalty on the par-3 14th, where he put his tee shot into a greenside bunker. Thinking he was removing a loose rock behind the ball, he instead touched what he called a "clump of sand."
He called for an official, who assessed a two-shot penalty, although the USGA later overturned the ruling, determining there was no intent and that McIlroy did not improve his lie. He ended up making par on the hole.
"They sort of went back and forth a little bit," McIlroy said of the USGA. "In a way, it came down to me and said, 'OK, are you comfortable telling us you didn't improve your lie?' And for me, I am comfortable saying that."
Tiger Woods won't be around for the weekend, withdrawing on Friday morning, releasing a statement that said he was dealing with "a mild oblique strain that led to pain and stiffness." He added he was "hopeful" of competing at the BMW Championship.
The top 30 players following next week's event will compete in the Tour Championship, Aug. 22-25 at East Lake Golf Club in Atlanta.
Kevin Kisner (70), Harold Varner III (67) and England's Ian Poulter (66) are tied for 12th at 8 under.
Merritt, after shooting a course-record-tying, 9-under-par 62 on Thursday, double-bogeyed the par-4 15th Friday after failing to advance his third shot from heavy rough. He then missed a putt of about 12 feet for bogey.
He also bogeyed the 18th.
"Would have been nice to get that last par putt to go in. Hit it just a little firm," Merritt said. "Any time you shoot something under par after a low round, it's pretty satisfying. It would have been nice to have something in the 60s today, but I'll take 70. Puts us right in the middle of things for the weekend."
Top-ranked Brooks Koepka is tied for 47th at 3 under after a second-round 69.
--Field Level Media