Dustin Johnson's caddie retrieves ball after accidental drop

PONTE VEDRA BEACH, Fla. -- Dustin Johnson did not hit his ball in the water at the fourth hole Friday, but his brother and caddie, Austin, was nonetheless forced to go into the water hazard to retrieve it.

Dustin had marked his ball on the green and then accidentally dropped the ball as he attempted to hand it off to his brother -- only to see it bounce into the water hazard.

That would be funny if not for the fact that the Rules of Golf require that players finish a hole using the same ball with which they started.

Dustin and Austin Johnson checked with a rules official to be clear and were told the golfer would be penalized if he didn't finish the hole with the ball that was now in the water.

"We made the right decision for once," Austin Johnson said.

With his shoes on, the caddie jumped off the green and into the shallow water, then located the ball and retrieved it. His shoes soaking wet afterward, Austin Johnson said he could see rocks and debris in the water and didn't want to risk cutting his feet.

"I've got more shoes," he said.

Under Rule 15-2, a substituted ball brings a two-stroke penalty. A ball can be marked, but it cannot be changed.

"The ball kind of slipped out of his hand," Austin Johnson said. "But he wasn't the one going down into the water."