About all anyone can say with certainty about No. 1 in the world is that it won't be Tiger Woods at the end of October.
It won't be Phil Mickelson, either.
Lee Westwood hobbled home from the Dunhill Links Championship at St. Andrews to rest his calf injury. He doesn't plan to compete again until the HSBC Champions in Shanghai at the earliest. By not playing, and through a gradual reduction of points, he will have a higher average than Woods in the ranking published Nov. 1.
But that doesn't guarantee Westwood will be atop the world ranking for the first time in his career.
Martin Kaymer moved to No. 4 with his fourth win of the year at the Dunhill Links, and the 25-year-old German can go to No. 1 if he wins the Andalucia Masters at Valderrama the last weekend in October.
"At the moment, for me, Lee Westwood is the best player in the world," Kaymer said.
And maybe not for long.
They all could meet in Shanghai - assuming Westwood is fit to play - and all four could have a shot at No. 1.
For most of the last decade, any debate about the world ranking took place around No. 50, not at the top. Aside from incentives in endorsement contracts, the real value of the ranking came from the majors giving exemptions to the top 50 (or the top 100 for the PGA Championship as it tries to assemble the strongest field).
Even those who didn't even try to understand how the ranking worked rarely quibbled about No. 1. That much was obvious.
Woods returned to No. 1 a week before the 2005 U.S. Open, and he stayed there by doing in five years what it has taken Westwood a career to achieve - 32 victories (along with five majors) and 15 runner-up finishes.
The question is why he stayed there so long this year.
Not only did he take off five months when his personal life imploded, Woods has only two top 10s this year, a tie for fourth in the Masters and U.S. Open. Because points are gradually reduced over a rolling two-year period, Woods has lost more world ranking points this year (330.105) than any other player has earned.
But it's important to understand what the world ranking is - and what it is not.
Just because a player is No. 1 in the world doesn't mean he's the world's best player. Anyone who has watched Woods over the course of the season can figure that out. It also was pretty clear in 2004 that Vijay Singh was the best golfer on the planet, yet the Fijian didn't rise to No. 1 until the sixth of his nine wins that season.
Being No. 1 simply means that player has compiled the best average (net points divided by number of tournaments) during a two-year period. The world ranking used to measure three years. The board could decide it should be only one year. Or one month.
In the last two years, Woods won seven times and finished in the top 10 in 58 percent of his tournaments. No one else has done that.
Mickelson has been No. 2 for most of the year, and he has been No. 2 longer than anyone in the history of the world ranking without reaching the top. Lefty has only himself to blame for that. He had 13 consecutive starts this year with a mathematical chance to replace Woods at No. 1 and didn't get it done, including a 78 in the final round at Firestone and a 76 in the final round at the TPC Boston.
Perhaps the player with the best case is Kaymer.
Not only has he won four times, he captured his first major at the PGA Championship, had top 10s in two other majors and has accumulated the most ranking points of any player in 2010. Then again, it's not only about winning, and it's not just about the majors. And the ranking is about more than one year.
That's where Westwood fits in.
During the last two years, Westwood has three wins, four seconds and four thirds. He was runner-up at the Masters and British Open this year, tied for third in the British Open and the PGA Championship last year. He won the Order of Merit on the European Tour. And he had to sit out for two months in peak form because of his calf injury.
Asked why he did not plan to take up PGA Tour membership last year, Westwood shared something that his manager, Chubby Chandler, had told him.
"Why would you take up membership in the States when you've been the most successful player in the world this year, through the injury, and you still have the great chance to go to world No. 1?" he said at St. Andrews. "You've come in second in two major championships. You must be doing something right."
It would be an amazing comeback for Westwood, who was No. 4 in the world in 2000, then fell out of the top 200 during a three-year slump. He never imagined back then that he could one day reach No. 1.
Not many could have guessed it might happen like this. Westwood's only win this year was the St. Jude Classic, made possible by Robert Garrigus taking triple bogey on the last hole. If Kaymer doesn't win at Valderrama, Westwood will rise to No. 1 without lifting a club, much less holing a putt. That would be OK with him.
"It's something I've always dreamed of, and it would be great if it happened," he said.
Sure, it might be anticlimactic, but that can happen when a ranking is based on math - addition, subtraction and division. It brings to mind the summer of 1999, when Woods easily dispensed of David Duval in that Monday night exhibition known as the "Showdown at Sherwood." A week later, when neither played, Duval went back to No. 1 in the world.
The following week, Woods won the PGA Championship and was No. 1 for the next five years.