Golf has been spoiled for the past few years.

Not spoiled the way Tiger Woods’ dominance spoiled us for so long.

But spoiled in that, for the past four years, there has been a star player step forward and own the sport, assert himself as the clear-cut No. 1 in the world.

Rory McIlroy was the first to do it, winning four times in 2014, including the British Open.

McIlroy then was succeeded by Jordan Spieth, who rattled off five wins in 2015, including the Masters and U.S. Open. It looked for a while like Spieth, who won twice more in 2016, was going to win every time he teed it up.

Then along came Jason Day, who went on a tear that included eight wins between 2015 and 2016, highlighted by first career major title, the 2015 PGA Championship.

Day held the No. 1 ranking for 47 weeks until a rainy February week in Los Angeles, when Dustin Johnson wrested control of the top spot by winning the Genesis Open at Riviera.

Johnson, who had been considered an underachiever in the major championships thanks to a number of calamitous crashes, asserted himself at last year’s U.S. Open at Oakmont, where he finally captured his first major. That U.S. Open title was one of six wins for Johnson since the 2016 season and is a big reason he is the current No. 1 in the world.

But now, with the 2017 U.S. Open upon us this week at Erin Hills in Wisconsin, the top level of the sport is a bit of a mystery again.

None of the four above-mentioned stars is considered the clear-cut favorite to win this U.S. Open. Each of them has shown his warts over the past year or so.

Johnson’s 2017 was derailed when he fell down some stairs at the house he was renting at Augusta and was forced to withdraw from the Masters before it began because of a back ailment. He hasn’t regained the form he had entering the Masters, when he arrived at Augusta having won his previous three starts and was a significant favorite to win the Green Jacket. Missing the cut at last week’s Memorial with scores of 78-74 did not help clarify his status as he attempts to become the first player to defend his U.S. Open title since Curtis Strange (1988-89).

Johnson, who remains ranked No. 1, went straight to Erin Hills for an unscheduled practice round the day after missing the cut at the Memorial. Had Johnson not three-putted from 12 feet on the final hole of the 2015 U.S. Open, won by Spieth at Chambers Bay, Johnson might be trying to win his third consecutive U.S. Open this week.

“It’s just a very, very difficult tournament to win,” he said. “[But] I like really tough golf courses. I tend to focus more and play better.”

Day had been having an uneven 2017 until he flashed with a runner-up finish at the AT&T Byron Nelson a few weeks ago. After barely making the cut at the Memorial, which is played in his adopted hometown, Day rallied on the weekend to finish tied for 15th by going 7-under in his final two rounds.

“I feel like I’m really close to putting everything together,’’ Day said at the conclusion of the Memorial.

At the Players Championship last month, Day spoke about being in the “rebuild stage’’ of returning to No. 1, saying “getting back to the top gradually gets harder and harder and harder.’’ He said his goal is “to have the single focus on playing and getting back to the No. 1 spot.’’

Spieth, like Day, has not had a poor 2017 season, he simply hasn’t come close to meeting the lofty expectations he set for himself after getting to No. 1. He has a win, a runner-up and two third-place finishes this season. His runner-up came just a few weeks ago at the Dean & Deluca Invitational, and he finished in a respectable tie for 13th at the Memorial.

“I’ve been putting myself in position to shoot low scores,’’ Spieth said, citing his ball striking. “I just haven’t quite converted to the level I have in the past.”

Like with Day, Spieth and everyone else around him expects better.

So, too, does McIlroy. But he has been slowed by a nagging rib injury that forced him to withdraw from both the BMW PGA Championship at Wentworth and the Memorial so he could rest up for Erin Hills.

“I am ready for Erin Hills and looking forward to playing there for the first time,” said McIlroy, who has gone nearly three years without adding to his four career majors. “The last few weeks have obviously been frustrating … but it was important I got back to a level of fitness where I felt like I could give myself the best possible chance at the U.S. Open.’’

McIlroy, the 2011 U.S. Open winner, doesn’t have a win this year. But he does have four top-10s in his six PGA Tour starts, including a tie for seventh at the Masters. So it isn’t like he has been chopping it up.

That can be said of all four of the most recent top players in the world. It is just that the golf world is waiting for one of them — or perhaps someone else — to seize the spotlight and become dominant, even if just for a few fleeting moments, to electrify the game.

This is what awaits us at Erin Hills this week.