Matt Kuchar completed a round of six-under-par 65 early on Saturday morning to claim a two-stroke lead after 36 holes of The Barclays, the opening event of the FedExCup playoffs.
Kuchar was at 11-under-par 131, with 2012 US Open champion Webb Simpson and long-hitting Gary Woodland tied for second at nine-under 133 at the halfway mark of the weather-hit tournament.
Twice major winner Rory McIlroy returned on Saturday to complete a 65 that featured eight birdies to join a group of nine at 136.
Graeme McDowell shot a second round of 72 and finished on one over par and missed the half way cut.
World number six Kuchar returned with 39 other players to complete the second round in windy conditions and put the event back on schedule after thunderstorms caused more than six hours of delays on Thursday's opening day.
The 35-year-old Kuchar birdied three of the five holes he had left to play, rolling in a 28-footer at the par-three 14th, and bogeyed the two others including the 18th.
"I was kind of hoping for nice, still conditions this morning, and some really good scoring conditions," said Kuchar, who has wins at the WGC-Accenture Match Play and the Memorial tournament this season.
"And 15, 20-mile-an-hour (winds, it was a little more challenging."
Kuchar will return to the course in the afternoon for the third round as scheduled.
Tiger Woods, playing in the same group as Kuchar, missed a 13-foot putt for birdie when play resumed at 14 after the suspension due to darkness on Friday, but birdied the 17th to improve to six under par, five shots off the pace.
"I was kind of hoping for nice, still conditions this morning, and some really good scoring conditions" - Matt Kuchar
South African Charl Schwartzel, the 2011 Masters winner, completed a second-round 67 to reach seven-under 135, a total he shared with reigning Masters champion Adam Scott of Australia, 2011 PGA champion Keegan Bradley and Rickie Fowler.
Along with world number one Woods, the group also included US Open champion Justin Rose and fellow Briton David Lynn, Spain's Sergio Garcia, Sweden's Freddie Jacobson and Jonas Blixt, Brandon de Jonge of Zimbabwe and American Jim Furyk.
With birdies flying on the rain-softened layout along the edge of New York harbor, the cut was set at even-par 142 with 80 players qualifying for the final two rounds.
Among those missing it were England's Ian Poulter (145) and American Brandt Snedeker (143), who entered the event in third place on the FedExCup points list.
The top 125 players on the list qualified for The Barclays. The leading 100 players on the points list will advance to next week's event, the Deutsche Bank Classic in Boston.