Padraig Harrington looked to have scuppered his slim Ryder Cup hopes after plummeting down the leaderboard at The Barclays in Farmingdale.
A day after he surged to the front of the field with a terrific seven-under 64, Harrington followed up with a four-over-par 75 and dropped into a share of 16th place, five shots off the eight-under pace set by Nick Watney and Sergio Garcia.
Europe captain Jose Maria Olazabal suggested on Thursday that even a victory for Harrington at the tournament might not be enough to earn him a wild card, when the team is announced on Monday.
The Irishman would have given Olazabal at least food for thought had he triumphed, but it will take a superb performance over the weekend now to rise back to the top.
The line-up at the event on Long Island is as strong as a major, and there are big guns including the likes of Tiger Woods and Vijay Singh between Harrington and the front-running duo.
Harrington began his second round on the back nine and was five over par for his round by the halfway stage, with a birdie at the long seventh - his 16th hole - the only shot he picked up all day.
American Watney, who is widely regarded as unlikely to be handed a wild card by Davis Love III for the United States Ryder Cup team, had an early eagle in his round of 69 which also featured four birdies and four bogeys.
Asked about his Cup prospects, Watney said: "It's very cliche, but I really can't control it, and I have so much work to do this weekend that if by some chance I would be in that conversation Sunday night, then great. But as of right now, it isn't really an issue."
Garcia followed an opening 66 with a 68, and the Spaniard who won last week's Wyndham Championships is booked in for Ryder Cup duty at Medinah next month.
Asked if there was anything about his current game he found pleasing, Garcia said: "I think I'm pretty much happy with everything that is going on."
Fijian Singh and American Bob Estes, aged 49 and 46 respectively, were one shot behind the leaders.
Singh posted a 67 and Estes went one better with a 66, a round bettered only by Sweden's Henrik Stenson who improved eight shots on Thursday by posting a 65.
Australian John Senden had a second 68 to stand six under, while Woods was in a four-man group on five-under 137 after a round of 69. His fellow Americans Rickie Fowler and John Huh stood alongside the former world number one, as did England's Gary Christian.
Level on three-under 139 with Harrington were the likes of Scotland's Martin Laird, Stenson, KJ Choi, England's Ian Poulter and Justin Rose, and Open Championship nearly man Adam Scott.
World number one Rory McIlroy drifted back to level par after a two-over 73, and that left him alongside Phil Mickelson and Luke Donald who both went round in 74.