Anirban Lahiri carded even par 71 in the second round to finish the first two rounds at four-under and dropped from overnight tied-14th to tied-35 at the halfway stage of the BMW Championship here.
Lahiri was done in by a disappointing finish over last three holes, where he bogeyed three times including two on the last holes in the second round.
Meanwhile, Marc Leishman, who shot 62 in the opening round, added 7-under 64 to open a three-shot lead over Jason Day (65) and Rickie Fowler (64) at Conway Farms. Patrick Cantlay (65) is in fourth place but six shots behind.
Lahiri opened with a string of seven pars before holing birdies on eighth and ninth holes to turn in two-under. A bogey on 13th was made up with a birdie on 15th, but closing bogeys on 17th and 18th spoilt his card.
Leishman was at 16-under 126, two short of the 36-hole record that Day set at Conway Farms two years ago on his way to a wire-to-wire, six-shot victory.
Day, who last won 16 months ago, chipped in from behind the 14th green for his second eagle of the week, and then added a third eagle with one swing, which was actually a hole-in-one on the Par-3 17th hole with a 7-iron that turned into a payoff for multiple parties.
That ace carried Day to a 65, putting him in the last group on the weekend with Leishman.
To mark his ace BMW awarded USD 100,000 to the Evans Scholars Foundation and then Day decided to give the car he won to the Evans Scholars, which will yield another full, four-year scholarship for another student.
Fowler also chipped in for eagle on the reachable par-4 15th hole on his way to a 64.
Leishman already has 18 birdies in 36 holes at Conway Farms, where the scoring average was a shade under 69 through two rounds.
It hasn't been easy for defending champion Dustin Johnson, who is facing putting problems. He finished bogey- bogey by taking two chips to get on the 17th green and hitting into the water on the 18th.
Phil Mickelson is trying to find his way into the top 30. He had two birdies, two bogeys and too many pars, but he did hit his approach to five feet on the par-5 14th for an eagle. His 69 took him to 7-under 135, in a tie for 12th.
Jordan Spieth, No. 1 in the FedExCup Playoffs, managed a 70 and joined Mickelson in the group at 135.