Rules official Mark Dusbabek said Davis played Zalatoris's ball and vice versa. Therefore, both players had to correct the mistake.

Will Zalatoris and Cam Davis were each penalized two shots for playing the wrong golf ball on the par-5 15th hole Sunday.

Under Rule 6.3c, it’s a two-shot penalty for each player who hit the wrong ball, and the mistake must be corrected by going back and playing the correct ball to finish the hole. Both Zalatoris and Davis did. Both made bogey when both would’ve made birdie.