The year’s final Major is not the only issue at stake this week at Valhalla, with Adam Scott and Phil Mickelson part of two intriguing subplots in Kentucky.
Rory McIlroy's fifth spell as World Number One could last a single week depending on results in the US PGA Championship.
McIlroy's victories in The Open Championship and WGC-Bridgestone Invitational have lifted the 25 year old above Scott in the Official World Golf Ranking, but only by 0.17 points.
Scott would reclaim top spot with a win on Sunday, regardless of where McIlroy finishes, and even a top-20 finish would be good enough for the Australian if McIlroy missed the cut and Sergio Garcia, Henrik Stenson and Justin Rose failed to win.
Garcia, Stenson and Rose can all become World Number One for the first time in their careers with a win, but they would also be reliant on McIlroy and Scott's results to varying degrees.
"I think the right guy is at number one at the moment," former Masters Tournament champion Scott admitted. "He's played the best over the last couple months.
"The guy who is winning the most tournaments probably should be the number one player and he's won three really big tournaments this summer and I've won one event.
"My consistent play is good, but you want the rankings to work and favour guys that win big events like that.
"I hope that I can go ahead and win this week and maybe go back to number one, but there's no doubt Rory has played the best golf over the last few months."
Phil Mickelson is confident he will improve his own record for Ryder Cup appearances when the qualifying period for the United States' team comes to an end on Sunday.
Mickelson is currently tenth in the points standings with the top nine at the conclusion sealing a place on the team for Gleneagles at the end of September.
The five-time Major winner has appeared in every Ryder Cup since making his debut in 1995 and is proud to have qualified automatically all nine times.
Asked if he thought he would receive a wild card from captain Tom Watson, Mickelson said: "I'm not to that point yet. I've got five more days here.
"I really do believe that after the way I played on the weekend, I think I'll continue that play into this week and I'm confident that I'll get on the team on my own and won't require that pick. I want to keep that streak going of two decades that I have."
Mickelson looked out of form for most of the WGC-Bridgestone Invitational last week, but carded a closing 62 to close the gap to former Masters champion Zach Johnson, who occupies the last automatic qualifying place.
The 44 year old's nine appearances is already a record for the United States - Nick Faldo played 11 times for Europe - although the left-hander has only tasted victory twice. The first came in the 'Battle of Brookline' in 1999 and the second here at Valhalla in 2008.
"It really is a fun place for us to play because of the memories that we have in 2008," Mickelson added. "Winning the Ryder Cup here was a very emotional experience and the people here in Louisville, we kept calling them our 13th man because they were such an asset to us in keeping us motivated, excited and giving us momentum.
"The course is in immaculate condition and I think that the set-up of it is sensational in that the fairways are a very fair width. There's nothing tricked up about the golf course.
"The greens are in perfect condition, pristine and you can really make a lot of putts if you get hot.
"The rough is challenging, but it's not hack it out; you have some decisions to make. It's just a very well thought out, wonderful set-up.
"The scores might be low if the rain comes in and the course is soft, but if it firms up a little bit it will be a real challenge because it is a long golf course."
