How Jordan Spieth can become world No. 1 at the PGA Championship

Jordan Spieth can become the No. 1 player in the world at this week's PGA Championship, unseating Rory McIlroy for the top spot.

Spieth had a chance last week at the WGC-Bridgestone Invitational to take No. 1 from McIlroy with a win but finished T-10 while McIlroy continued to sit out in favor of making a return from a July 4 soccer injury at the season's final major.

This time around, Spieth doesn't have an unabated path to the top.  If McIlroy wins or finishes solo second at Whistling Straits, he will remain No. 1 no matter how Spieth finishes. There are five scenarios, however, where Spieth can become No. 1:

1. Spieth wins and McIlroy is not second alone.

2. Spieth is second alone and McIlroy is not in the top 6.

3. Spieth is tied second with one other and McIlroy is not in the top 13.

4. Spieth is tied second with two others and McIlroy is not in the top 33.

5. Spieth is third alone and McIlroy misses the cut.

At a minimum, Spieth must finish no worse than third alone, which would give him one of the greatest major championship seasons ever. That's a big ask with a potentially huge reward.