Rory McIlroy had a two-shot penalty rescinded at The Northern Trust after it was determined he had not intended to improve his lie in a bunker.
McIlroy was punished on the course after finding the bunker on the par three 14th at Liberty National.
The Northern Irishman bent down to remove what he thought was a small stone behind his ball but, when he touched it, McIlroy realised it was just a clump of sand.
McIlroy told rules officials what he had done, and he was originally given a two-shot penalty as it was considered he could have tested the surface.
But PGA Tour rules officials later reversed the decision, and McIlroy eventually carded a three-under-par 68 to leave him tied for seventh and three shots adrift of halfway leader Dustin Johnson.
"It's such a grey area and it came down to me," McIlroy said after his round, adding that he had accepted a two-stroke penalty on the New Jersey course because he did not want to hold up play.
"I thought it was a rock; it wasn't. I moved my hand away and then I was like, I don't know if I've done anything wrong here.
"The reason I called someone over is I don't want anything on my conscience, either.
"I feel like I play the game with integrity and I'm comfortable saying that I didn't improve anything."
Johnson has a one-shot lead over Jordan Spieth at the first regular post-season FedEx Cup event.
Abraham Ancer, Troy Merritt, Patrick Reed and Jon Rahm are a further shot back.
Englishman Justin Rose and McIlroy are among a group of five players on nine under.
