Miami - Former Masters champion Patrick Reed was penalised two strokes on Friday for improper swings in a waste bunker in the third round of the Hero World Challenge in the Bahamas.
Reed, who is due to tee it up on playing captain Tiger Woods' US team in the Presidents Cup next week, insisted he didn't think he improved his lie.
But he acknowledged that he moved sand with both practice swings and therefore violated the rules.
"It's unfortunate," said Reed, whose bogey at the 11th was changed to a triple-bogey eight.
"I didn't feel it drag, but then when they brought it up to me it definitely did drag some of the sand and because of that it's considered a two-stroke penalty," he said.
"I think with a different camera angle they would have realised that if it was from the side you would have seen that with the backswing it was not improving the lie because it was far enough away from the golf ball.
"But after seeing that camera angle, because it brushed the sand it was a penalty."
Slugger White, PGA Tour vice-president of rules and competitions, said the matter was clear cut.
"You cannot remove or press down loose soil or sand, that's the bottom line," White said, noting that Reed's intent was irrelevant.
Reed, who bogeyed the 12th, had recovered with birdies on 14 and 15 and after a bogey at 16 birdied the last. But the penalty meant he lost his share of second as he finished with a 74 that left him alone in sixth, three strokes behind US Open champion Woodland.
Woodland finished with back-to-back birdies in a 68 at Albany Golf Club for a 13-under par total of 203 and a one-shot lead over Sweden's Henrik Stenson.
Stenson also carded a 68 to finish the day on 12-under. He could have taken sole possession of the lead or at least tied but bogeyed the par-four 18th.
Tournament host Woods, meanwhile, was lurking just two off the lead on 11-under with Justin Thomas and Spain's Jon Rahm.
Former world No 1 Woods, who is also plotting the United States' Presidents Cup campaign in Australia next week, fired a five-under-par 67.
Woods' round included six birdies and one bogey, with the 15-time major winner mounting a charge on the back nine.
A 20-foot putt to save par on the 10th ignited his challenge, and Woods' putter came to the fore on the 11th when he drained another 20-footer for a birdie.
Back-to-back birdies on 14 and 15 took him to four under before a birdie three on the last, set up with a sublime sand wedge from the fairway to eight feet, completed his 67.
Leading third-round scores on Friday in the unofficial Hero World Challenge golf tournament hosted by Tiger Woods at Albany Golf Club in New Providence, Bahamas (USA unless noted, par-72):
203 - Gary Woodland 66-69-68
204 - Henrik Stenson (SWE) 69-67-68
205 - Tiger Woods 72-66-67, Justin Thomas 69-69-67, Jon Rahm (ESP) 70-66-69
206 - Patrick Reed 66-66-74
210 - Chez Reavie 68-73-69, Rickie Fowler 69-69-72, Justin Rose (ENG) 69-70-71
211 - Matt Kuchar 71-70-70, Kevin Kisner 71-70-70
212 - Webb Simpson 73-68-71
213 - Xander Schauffele 73-70-70
214 - Jordan Spieth 75-70-69
216 - Tony Finau 79-68-69, Bubba Watson 72-73-71
217 - Bryson DeChambeau 76-71-70, Patrick Cantlay 74-72-71