Phil Mickelson changed balls mid-round. Did he break a rule?

Phil Mickelson, Tim Mickelson

Phil Mickelson and caddie — and brother — Tim Mickelson on Thursday on the 9th tee at Oak Hill Country Club.

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Nick Piastowski

Nick Piastowski

Nick Piastowski is a Senior Editor at Golf.com and Golf Magazine. In his role, he is responsible for editing, writing and developing stories across the golf space. And when he’s not writing about ways to hit the golf ball farther and straighter, the Milwaukee native is probably playing the game, hitting the ball left, right and short, and drinking a cold beer to wash away his score. You can reach out to him about any of these topics — his stories, his game or his beers — at nick.piastowski@golf.com.