AUGUSTA, Ga. — The Masters should be the easiest to predict of golf’s four major events.

It got a lot harder Wednesday when Dustin Johnson, the betting favorite and No. 1 player in the world, took a serious fall down a staircase at his rented home and wasn’t sure he could even tee it up at Augusta National.

His agent, David Winkle at Hambric Sports Management, said Johnson landed “very hard on his lower back.” He was treating it with ice and medication, and told to remain immobile.

Winkle said Johnson hopes to play.

He is scheduled for the last group at 2:03 p.m. Thursday.

The Westgate Las Vegas SuperBook immediately dropped the odds of Johnson winning from 11-2 to sharing the top at 7-1 with Jordan Spieth and Rory McIlroy.

Telling were the comments Johnson had made Tuesday, when he was talking about the state of his game after three straight victories.

“I’ve got a lot of confidence in my game right now, especially with the way I’ve been playing the last few tournaments,” Johnson said. “But, you know, anything can happen.”

That’s true at just about every Masters.

Johnson’s status only adds to the mystery at the year’s first major.

The Masters has the smallest field, with just 94 players, and that’s before history starts eliminating about 40 percent of them.

No amateur has ever won and five are in the field this year. There are 19 players at Augusta National for the first time, and not since 1979 has a Masters rookie (Fuzzy Zoeller) won. No one older than 46-year-old Jack Nicklaus has won, so that wipes out 11 more players.

No one has ever won his first tournament at the Masters, which doesn’t bode well for Roberto Castro or Kevin Chappell. And only three players since the Masters began in 1934 have ever won back to back. Sorry, Danny Willett.

So who does that leave?

The obvious choices would be Johnson (presuming he recovers), McIlroy or Jason Day, the top three players in the world. Impossible to overlook is Spieth, who has never finished worse than runner-up in his three Masters.

But in the last 10 years, only one player from among the top three in the world won the Masters – Phil Mickelson (3) in 2010.

“That’s what makes the golf course wonderful, actually, and what a great tournament it is,” Nicklaus said. “Because you really never know what’s going to happen. Even the players, as good as they might be, don’t know.”

The tournament starts Thursday with a course that figures to be softened by rain, which could be good news for McIlroy. It could also be confounding because of wind that always feels stronger than it really is among the Georgia pines, which could be bad news for McIlroy.

For Johnson, this is an opportunity to pronounce his dominance. Not since Hubert Green in 1976 has a player won three straight events going into the Masters. Green tied for 19th that year. The only player to make the Masters his fourth straight win was Jimmy Demaret in 1940.

Augusta National can favor emotion. Who can forget Ben Crenshaw winning days after he was a pallbearer for swing coach Harvey Penick?

That might bode well for Day, who said he wasn’t sure he was going to play a few weeks ago when he brought his mother from Australia to have surgery for lung cancer. Odds for a recovery suddenly are much stronger, and Day has said her health has been on his mind all year.

“I owe everything to her,” Day said.

And for Spieth, there is a chance to erase a bad memory of his back-nine meltdown a year ago.

“We’ll step out and try and get a chance to win on Sunday on the back nine again,” Spieth said. “That’s all we’re asking for. That’s it. Just that small little piece.”

Johnson can only ask for a chance to play.