Spieth will play the Bridgestone, setting up the possibility that he could overtake McIlroy in the rankings.
But today, McIlroy is still the No. 1-ranked player in the world (by a slim margin). Whether he's still the best player in the world is no longer a fact, but a rich subject for debate.
It's unclear when McIlroy might return from his ankle injury, whether he'll make it back in time to defend his title at the PGA Championship next week or if the injury will linger into the fall. But if Spieth wins this week, or if he merely maintains his strong play with McIlroy out, we could have a new No. 1 player in the world for the first time in a year.
What seemed like a friendly, but brazen declaration by Spieth after he won the Masters -- I'm not in your league just yet, but I'm coming for the king -- is suddenly on the cusp of becoming a reality.