No knowledge, no foul

There's a very small chance Dustin Johnson used a ball that did not conform to regulations set by the United States Golf Association when he won the AT&T Pebble Beach National Pro-Am. Whether or not he did won't affect his title, and of course the infinitesimal advantage he may have gotten from the ball had no bearing on his four-stroke victory. Johnson uses the TaylorMade TP Red LDP ball. TaylorMade has admitted some of the balls exceed the USGA initial velocity limit, and voluntarily removed the ball from the USGA's Conforming Ball List, effective March 2. The company claims less than two thousandths of all TP Red LDP balls produced violated the velocity rule. The company said it occurred because the wrong core was placed inside the TP Red balls.
It was unknown whether Johnson used a nonconforming ball, but according to the PGA Tour’s standard rules policy, no action would be taken against the Myrtle Beach resident because the ball was on the Conforming List at the time of his victory.