Harrison Frazar, William McGirt and Matt Kuchar share the lead after bad light brought a premature end to round one of The Barclays in New Jersey.
American Frazer shot a flawless seven-under-par 64 to set the clubhouse lead, while his compatriots Kuchar and McGirt had completed 16 and 11 holes.
Justin Rose leads the British challenge on four under after 16, while Luke Donald is one under after 14.
However, the threat of Hurricane Irene continues to hang over the tournament.
The hurricane, which has already battered the Bahamas, is working its way up the east coast of America, and is expected in the New Jersey area on Saturday.
"With the way the weather is coming, I didn't want to have to sit around and play too much [on Friday] or Saturday," said Frazar.
"It's going to be a long week by the time this thing is over."
Three hours of the opening round were disrupted by rain meaning world number one Donald was among 51 golfers who were unable to finish their rounds.
The Englishman is bidding to become the first winner of the US and European money lists in the same season and he began his round with a bogey at the first but he recovered with birdies on the fifth and ninth before the poor light curtailed his round at one under after 14.
The 33-year-old leads the overall money list in the US and is also top of the European Tour equivalent Race To Dubai.
The Barclays is the first of four FedEx series events, the end-of-season competition in which Donald lies fourth on the points list.
Defending FedEx champion Jim Furyk, who denied Donald to win the lucrative $11m purse last year, opened with a level par 71.
Donald's playing partners, US PGA champion Keegan Bradley and Phil Mickelson, were both two under.
The first round will resume at 1215 BST with the second round starting half an hour later.