Ryan Moore noticed his ball move ever so slightly as he went to tap in a 10-inch putt for par on the 11th hole. He didn't think it was a penalty because the rule had changed for this year.

Not quite.

Rule 18 2-b was changed to avoid what happened to Webb Simpson at New Orleans last year. Simpson went to tap in for par when a gust of wind moved his ball. Under the new rule, if an outside agency moves the ball — wind is the best example — the player replaces the ball without penalty. The difference Friday at the Wells Fargo Championship is there was virtually no wind. The ball simply became unsettled and moved.

Moore was assessed a one-stroke penalty, giving him a 70 and leaving him three shots behind Nick Watney going into the weekend.

"Today I got a penalty stroke for absolutely no reason," Moore said. "I went to address my little tap-in and set into it and set my putter down behind it. Took my stroke back and the ball just settled a little bit. I thought that was the whole point of the ruling change from last year that Webb had incurred. But it turns out the ruling didn't really change anything. It's still a penalty, even though I had nothing to do with my ball settling into a lower spot."

PGA Tour rules official Steve Rintoul said the ruling is simple. If a player addressed the ball and the ball moves, he was deemed to have forced it to move.

"The new exception to the rule that's got everybody hung up is the exception refers to if a wind or an outside agency, like a bee or a fly on the green, had caused the ball to move, we can get him out if it he's virtually certain that he didn't cause it," Rintoul said. "But in this case, we've got no wind. We've got nothing else down there, and the decision specifically refers to gravity. If a ball moves because of gravity, that's just part of the game."

Moore accepted the penalty, though he wasn't happy about it.

"I certainly did not make the ball move, and I thought that was the whole point of the rule change," he said.

About the only thing that made Moore happy was his position. He was in the hunt going into the weekend at Quail Hollow, and playing well.

"I'm right there in the mix and I've proven I can shoot some good scores out here," Moore said. "Just need a couple more this weekend."


BIRTHDAY BOY: He already has won the U.S. Open and been to No. 1 in the world on two occasions. Sometimes it's hard to remember that Rory McIlroy is only 23.

McIlroy celebrated his birthday Friday by opening with two straight birdies and closing with a birdie on the tough par-4 ninths for a 68 that put him six shots back going into the weekend at the Wells Fargo Championship. When he won at Quail Hollow two years ago for his first PGA Tour win, his birthday wasn't until Monday after the tournament.

It was quite a celebration. This one? Not so much.

"I don't have much going on," McIlroy said. "Probably just go out for a nice dinner and take it easy and get ready for tomorrow."

Still, he rarely finished a hole without someone in the gallery reminding him of his birthday, as if he needed it. McIlroy, playing for only the second time in the last two months, doesn't feel as though he has done anything special, yet he has posted two decent rounds and is close enough to the lead halfway through the tournament. Two years ago, he made the cut on the number and won.

"So being only six back should be easy," he said, laughing. "But no, the guys at the top of the leaderboard are obviously playing well. I'll go out and get off to a good start tomorrow and post a good one to give myself a chance going into Sunday."


TOUGH FINISH: Vijay Singh, back from Germany where he received treatment on his back, opened with a 68 and was creeping up the leaderboard Friday.

It didn't last long, and he won't get another chance to improve. In a shocking finish, Singh took triple bogey on the 18th hole and had a 77 to miss the cut.

He wasn't the only one who was hurt by a poor finish. Rory Sabbatini was in good position to make the cut until he took a triple bogey on the 17th hole, then went from a shallow lie in the creek to drowning one in the creek by the green, leading to a make a double bogey. That gave him a 41 on the back for a 78.


HOUSEGUEST: Nick Watney and Webb Simpson will be in the final pairing Saturday. They will be under the same roof Friday night.

Watney is saying at Simpson's house a short drive from Quail Hollow, so it was a coincidence that both wound up atop the leaderboard going into the weekend. Watney had a 64 and was at 132, while Simpson was another shot behind after a 68.

Simpson cooked out on Monday to celebrate the birthdays of Watney's and Jason Day's wives. Other than that, it has been low key. But there was a house bet — whoever had the highest score had to take out the garbage.

"He's got to take it out," Watney said. I got a 68 yesterday and had to take it out. So far, it's been a tough house."


DIVOTS: Bo Van Pelt withdrew from the second round because of a wrist injury. Earlier on Friday, Anthony Kim withdrew before the start of the round because of lingering pain in his right elbow and wrist and left thumb. ... Quail Hollow played under par for the second straight round. ... Phil Mickelson has the lowest scoring average at Quail Hollow with at least 16 rounds. He has never won, but has finished out of the top 10 only twice in eight previous trips.