Tiger Woods was unable to build on his first-round lead at The Barclays, slipping back on Friday with a second round that included four bogeys.
Woods missed a two-foot putt for one of his four bogeys over his final eight holes at Ridgewood Country Club as he settled for a two-over 73 for four-under 138.
The world number one was still in the hunt in the first of the US PGA Tour's FedEx Cup playoff tournaments, although he will have to make up ground.
Australia's Jason Day, who won his first US PGA Tour event at the Byron Nelson in May, reeled off three birdies in a row late in his round en route to a four-under 67 to seize the clubhouse lead on eight-under 134.
He was one shot in front of Kevin Streelman and Vaughn Taylor. Streelman carded a 63 and Taylor, who shared the overnight lead with Woods, a 70 for 135.
Woods is at least assured of remaining world number one for another week.
Phil Mickelson, who again had a chance to overtake Woods, missed the cut and departed without discussing his round.
Woods had created a stir on Thursday when he fired a six-under 65 to seize a share of the first-round lead alongside Vaughn Taylor.
The round was his lowest since a sex scandal erupted around him last November and came three days after Woods's divorce from Elin Nordegren was finalised.
Woods entered the tournament ranked 112th in FedEx Cup points and needing to reach the top 100 to qualify for next week's event in Boston.
A victory would see him jump to the top of the list, and he must finish at least 57th to advance.
Woods seemed confident a victory remained within reach.
"You play around here and post good numbers, you'll move up the board," he said. "The guys aren't going to be tearing this place apart."
With Europe's Ryder Cup team to be finalized on Sunday, Ireland's Padraig Harrington was pleased with a 68 that put him on 137.
"The last thing I wanted was to come here and miss the cut, or play poorly here," said Harrington, who is hoping to be a captain's pick.