OAKMONT, Pennsylvania (AFP) - Dustin Johnson was making a final push for the US Open title on Sunday with the possibility of a one-stroke penalty looming.

With just one stroke separating Johnson from Shane Lowry atop the leaderboard, the matter could make for a messy ending to the championship. Johnson was told at the 12th hole that the US Golf Association (USGA) wanted to review video of the incident with him.

It occurred at the fifth green, where Johnson's ball moved slightly before his par putt.

He spoke with a rules official with his group, and it was determined he did not cause the ball to move so no penalty was assessed.

But Johnson and his nearest rivals on the course were informed that he could still incur the penalty.

Lowry actually called a penalty on himself for the infraction at issue, at the 16th hole in the second round.

It is yet another major complication for Johnson, the world No. 6 who has endured a string of near misses in golf's biggest events, including a three-putt at the 72nd hole of last year's US Open that handed the title to Jordan Spieth.

The USGA's handling of the matter caused a stir on social media, with pro golfers weighing in.

"This is ridiculous... No penalty whatsoever for DJ. Let the guy play without this cr** in his head. Amateur hour from @USGA," tweeted world No. 3 Rory McIlroy, who missed the cut at Oakmont.

World No. 2 Spieth, who finished his fourth round earlier, added: "Lemme get this straight.. DJ doesn't address it. It's ruled that he didn't cause it to move. Now you tell him he may have? Now? This a joke?"

PGA Tour pro Brandt Snedeker tweeted: "Hey @USGA, it's impossible for DJ to cause the ball to move backwards!!!!!!! #commonsense."