That post was followed by an event listing on the Ozzfest Facebook page declaring that the "Ozzfest Meets Knotfest 2017 Announcement" will be happening on July 10th.
More than likely the show would be a two day stand alone event. This is similar to last year's stand alone festival at San Manuel Amphitheater and Festival Grounds in San Bernardino, California which featured Ozzfest on one day and Slipknot's Knotfest on the second.
Ozzy started rumors with this tweet ...