ATLANTA (AP) The most compelling competition in golf used to be who would emerge as a veritable rival for Rory McIlroy.
Just one year later, McIlroy is No. 3 in the world.
That's likely to change by the end of the year because McIlroy is really good and he still has four more tournaments to play. But to look back makes for an interesting question going forward:
What will golf look like one year from now?
Because if 2015 was any indication, this could be the start of either a ''Big Three'' or a really big crowd.
Players in their 20s won 24 of the 47 tournaments on the PGA Tour schedule this year, the most since the tour began keeping such records in 1970. And for the first time since the world ranking began in 1986, there has been a different No. 1 player for six consecutive weeks.
Consider where some of the leading players were when the PGA Tour season ended last year.
McIlroy looked unstoppable. He won the British Open and the PGA Championship, with a World Golf Championship title in between, and he built such a big margin in the world ranking that it looked as though he would hold that spot down for years to come.
Who was going to take it away from?
Jordan Spieth had gone 35 tournaments and 14 months since his only victory, the John Deere Classic. He won that as a 19-year-old rookie by holing out from a bunker on the 18th hole and getting another chance when David Hearn missed a 3-foot putt for the win in a playoff. No one was calling him ''Golden Child'' back then.
Jason Day was still somewhat of a mystery. He finally picked up his second PGA Tour victory in the Match Play Championship early in the 2014 season, only to be sidelined with yet another injury. He didn't finish within seven shots at any of the majors.
Rickie Fowler finished in the top five at all four majors. The good news? At least it took attention away from the fact he only had one PGA Tour win in five years. Dustin Johnson was nowhere to be found. He was in the second month of what turned out to be a six-month break from golf to get help for ''personal challenges.''
And it's worth mentioning Tiger Woods. His year was disrupted by back surgery, though he still was No. 16 in the world and was taking the rest of the year off to get fully healed. Expectations were strong until he bladed that bunker shot over the green and into the grandstands during the Phoenix Open pro-am.
Look at how much the landscape has changed since then.
Spieth accomplished more in seven months than some players do in an entire career - the Masters, U.S. Open and Tour Championship among his five victories, a record $12 million to win the money title and at age 22, the second-youngest player behind Woods to reach No. 1 in the world.
Day also won five times this year. He won his first major at the PGA Championship, where he set a record as the first player to finish a major at 20-under par. He reached No. 1 in the world for one week after winning the BMW Championship. Odds are the 27-year-old Aussie will get there again.
Fowler couldn't even beat Ian Poulter in an anonymous survey of his peers. They tied for most overrated. But there was nothing overrated about the way he won The Players Championship with an eagle-birdie-birdie finish in regulation, and two more birdies on the island-green 17th at the TPC Sawgrass. He birdied two of his last three holes to win the Scottish Open and rallied to win at the TPC Boston.
And it's not like McIlroy went into a slump.
He won in Dubai early in the year, and when the spotlight began to shine on Spieth in a green jacket, McIlroy responded by winning the Match Play Championship and the Wells Fargo Championship in a span of three weeks to remind the world that he could still play this game.
He just can't play soccer as well. A freak ankle injury kicking around the ball with friends in Northern Ireland kept McIlroy out for two months and prevented him from defending his title at St. Andrews.
After the Presidents Cup, Day is taking the rest of the year off to get even stronger and more fit. His work ethic is frightening. Spieth has two trips to Asia in the next month (Presidents Cup, HSBC Champions) and two titles to defend in Australia and The Bahamas. His biggest challenge is what to do for an encore.
Spieth, Day and McIlroy shared the stage in a banner year for the PGA Tour. A one-man show turned into a Three Ring Circus.
Nothing immediately. Barring any schedule changes, these three won't be in the same tournament for another five months.