The ruling behind that strange Zach Johnson putt at Travelers

Zach Johnson carded one of the stranger pars you'll ever see during the Travelers Championship's second round.

On the third hole, Johnson watched his ball fall into the cup all on its own, and then had to pull it out and tap it in himself.

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"It's almost like it stopped. Moved. Stopped. Moved. That's the best way I can explain it." That was how Johnson explained the odd circumstances surrounding the bizarre putt on No. 3 to PGA Tour rules official John Mutch.

Johnson took aim, 18 feet away from the pin. His putt was dead on, creeping up to the hole and sitting on the lip. In accordance with Rule 16-2, Johnson counted the allotted 10 seconds before addressing the ball to tap it in. Sure enough, right after his ten seconds elapsed, Johnson addresses the ball and before hitting it, the ball wobbles itself in.

Here's something you don't see every day.https://t.co/xS8EHldtT1 pic.twitter.com/EHAzoF0kiu

— PGA TOUR (@PGATOUR) June 23, 2018

After some deliberation, the ball was returned to the lip for a fourth shot, giving Johnson a par instead of what appeared to be a birdie. Per Rule 16-2:

"When any part of the ball overhangs the lip of the hole, the player is allowed enough time to reach the hole without unreasonable delay and an additional ten seconds to determine whether the ball is at rest. If by then the ball has not fallen into the hole, it is deemed to be at rest. If the ball subsequently falls into the hole, the player is deemed to have holed out with his last stroke, and must add a penalty stroke to his score for the hole; otherwise, there is no penalty under this Rule."

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Johnson further discussed the curious case of his wobbling ball after the round.