Tiger Woods has been ranked the world's top golfer for 270 consecutive weeks, but that run could end this weekend.
Woods, who has won seven times at Firestone, could be passed by Phil Mickelson and Lee Westwood. Woods is paired with Westwood for the first two rounds tomorrow and Friday.
According to pgatour.com, a victory by Mickelson on Sunday and he'll replace Woods, regardless where Tiger finishes. Woods has been the top player in the world for a total of 612 weeks.
Westwood, ranked third, could supplant Woods with a victory and Woods finishing worse than a two-way tie for second.
According to the Web site, Mickelson must finish at least fourth to have a shot at the top ranking. Even finishing fourth, he'll need Woods to finish at least 38th.
Mickelson said supplanting Woods as the top-ranked player "absolutely" means something to him.
"It would be a very important thing," he said Tuesday. ''But it's not something I'm focusing on as much as it is trying to get my game sharp for these upcoming events, the final playoffs as well as the majors."