Kuchar, who completed five holes of his second round Saturday morning for a 6-under 65 and a two-shot lead, was tied with Woodland on the reachable par-4 16th when his putt ran into a sprinkler and stopped, costing him a reasonable chance at birdie. He wound up with a 70 in the third round.
Woodland had a one-shot lead until his tee shot on the 17th plugged in the far end of the fairway bunker, effectively costing him a full shot. He blasted out sideways, made bogey and had to settle for a 68.
They were at 12-under 201, one shot ahead of Kevin Chappell, who broke the tournament course record with a bogey-free 62.
Chappell's round was so strong that it was 10 shots better than the average score at Liberty National, where the wind was blowing about 10 mph.
"In the wind, if you would have told me someone was going to shoot 62 today, I would probably have laughed at you," Chappell said.
Tiger Woods spent another round grabbing his lower back and bending over gingerly to put his ball on the tee and retrieve it from the cup. He was on the fringe of contention for much of the blustery afternoon until two solid shots on the par-5 13th for a birdie, driving the 16th green for a two-putt birdie and closing with a 10-foot birdie putt on the 18th for a 69 that left him very much in the picture at 8-under 205.
"It starts off great every day, and then it progressively deteriorates as the day goes on," Woods said of his lower back, which he hurt from what he said was a soft bed in his hotel room. "Hopefully, tomorrow it will be one of those days again. Fight through it and see if I can win a tournament."
David Lynn of England, who earned his PGA Tour card a year ago from his runner-up finish in the PGA Championship, also had a 69 and was tied with Woods, four behind. The large group at 7-under 206 included 20-year-old Jordan Spieth, Bubba Watson, Jim Furyk, Justin Rose and Rickie Fowler.
With a dozen players separated by five shots, pure greens at Liberty National and limited rough, the first event of the FedEx Cup playoffs is still very much up for grabs.
Chappell's round was evidence that even in windy conditions, low scores are available. For the former UCLA Bruin, it was really was simple as making putts, most of them in that 10-foot to 15-foot range. There were a few par saves on the back nine, and six birdies on the front.
"I just really holed all the putts that you kind of expect to hold but you don't always hole," he said.
Kuchar and Woodland will be in the final group for the second straight day, and they certainly aren't strangers. Their caddies knew each other from the LPGA Tour, and they became friendly enough that Kuchar picked Woodland to be his partner in the World Cup two years ago. The Americans won for the first time in over a decade.
Earlier this week, they were at the Braves-Mets game and went into an indoor batting cage. Kuchar pitched and was impressed with how well Woodland swung the bat, which is not to say he was surprised.
Woodland is regarded as one of the best athletes on tour -- a promising baseball player in high school who first went to a Division II school to play basketball and then transferred to Kansas to play golf.
But he has disappeared since winning at Innisbrook two years ago, mainly from injuries to both wrists. He began working with Claude Harmon in the spring, and he hired mental coach Julie Elion right before his season turned around by winning the Reno-Tahoe Open.
"I've really let my game take over," Woodland said.
He surged into the lead during a four-hole stretch to close out the back nine -- a 5-iron into the par-5 sixth, a sand wedge to 10 feet for birdie on No. 7, a 4-wood for his second shot on the par-5 eighth for birdie, and a 6-iron for a fourth straight birdie on the ninth.
Kuchar caught up by playing bogey-free on the back nine.