The PGA Tour knows the LIV series is a threat, so it had to make the significant changes announced Wednesday

PGA Tour commissioner Jay Monahan said the Saudi-backed LIV is trying buy the game of golf.Seth Wenig/Associated Press

The PGA Tour faces a threat never before seen from the major American professional sports leagues. And commissioner Jay Monahan knows it.

“We welcome good, healthy competition. The LIV Saudi Golf League is not that,” Monahan said Wednesday at the Travelers Championship in Cromwell, Conn. “It’s an irrational threat — one not concerned with the return on investment or true growth of the game.”

The NBA had competition in the 1970s and the NFL in the 1980s, but financial troubles did in the ABA and USFL. The NHL loses a few aging star players to clubs in Europe, but is still the hub for the world’s premier talent. Major League Baseball has never had any competition.

But the LIV Series is a different beast. Backed by the investment arm of the Saudi government, it is not here for profit. It is here to disrupt the golf world and bring prestige to the Saudi royal family.

“The PGA Tour, an American institution, can’t compete with a foreign monarchy that is spending billions of dollars in an attempt to buy the game of golf,” Monahan said.

Monahan is right. The PGA Tour cannot match the nine-figure guarantees LIV is offering to golf’s biggest names. Wednesday, LIV officially announced it had signed four-time major winner Brooks Koepka as the latest star player to defect from the PGA.

In response to the tide of defections in recent weeks, Monahan and the PGA Tour announced significant changes that begin in 2024. They include increased purses in eight events, a shorter schedule, a smaller FedEx Cup playoff field, and a new three-event European series in the fall for the top 50 players in the FedEx Cup standings.

They are an acknowledgment that the LIV threat is very real, and that the only way to stop the defections is to cater to the PGA Tour’s star players.

“I think everyone’s concerned,” said world No. 6 Patrick Cantlay. “If the PGA Tour wants to remain the preeminent tour for professional golfers, it has to be the best place to play for the best players in the world.”

The LIV threat didn’t seem serious when only over-the-hill professionals, such as Phil Mickelson, Lee Westwood, and Ian Poulter, and youngsters who have not made their mark, such as 2021 US Amateur champion James Piot, signed on.

But LIV is starting to reel in some of the top players, such as Dustin Johnson (38 years old), Patrick Reed (31), Bryson DeChambeau (28), and Koepka (32). Justin Thomas and Collin Morikawa combatted defection rumors this week and tweeted they are staying with the PGA Tour.

But Koepka was committed to the PGA Tour, until he wasn’t. The LIV money was simply too good to pass up.

After sticking with the PGA, Brooks Koepka changed his tune and signed with the LIV series.Jessica Rinaldi/Globe Staff

“That was definitely a surprise for me. I was at a function with him last week and definitely wasn’t what he had in mind,” world No. 1 Scottie Scheffler said. “We were focused on building the PGA Tour and getting the guys that are staying here together and kind of just having talks, and figuring out how we can help benefit the Tour.”

There’s no stopping the Saudis and their cash reserves. That’s why the changes by Monahan were all about the star players. There was no talk of a guaranteed salary or minimum appearance fee, topics that have been raised by LIV.

The world’s top players don’t care about appearance fees. They want fatter purses. And a better schedule. And more freedom to play events elsewhere.

Monahan and the PGA Tour conceded those points after a five-hour meeting with player representatives Tuesday in Connecticut.

The biggest changes:

▪ The purses at eight of the Tour’s most popular events will increase by a total of $54 million.

▪ Instead of a year-round schedule that begins in the fall, the Tour will operate in a single calendar year that begins in January. Once the playoffs conclude in August, the fall season will be optional and not for FedExCup points.

“Selfishly, for me, I would like an offseason,” PGA Tour player director Rory McIlroy said. “I would like to not turn up in February and be 150th in the FedEx Cup point list because I just didn’t want to play in the fall and I wanted to take some time off and spend some time with my family.”

▪ The FedEx Cup playoff field will shrink from 100, 70, and 30 participants at the three events to 70, 50, and 30. The smaller the field, the better the chances for the star players to emerge with the top prize.

▪ The three international events will be held after the fall season, though details are scarce. It’s a way to reward the top players with destination events.

Monahan knows even these changes may not be enough to stem the LIV defections. He spent much of his press conference appealing to players’ sensibilities, highlighting concepts such as “honor,” “legacy,” and “competition.”

“Our members compete for the opportunity to add their names to history books … without having to wrestle with any sort of moral ambiguity,” he said.

The real key for PGA Tour sustainability, though, is the majors. The United States Golf Association allowed the LIV golfers to play in last week’s US Open, and the Royal & Ancient is allowing them to play in next month’s British Open. Augusta National and the PGA Championship have not had to make any decisions yet.

“I would never risk going and losing the opportunity to go back to Augusta every year or to do any of it,” said Scheffler, this year’s Masters champion.

Scottie Scheffler says he's sticking with the PGA Tour.Matthew J. Lee/Globe Staff

Most of Scheffler’s contemporaries might agree. But jumping to LIV carries little risk right now because the majors are still in play. The only consequence of jumping to LIV is you can’t play in regular PGA Tour stops such as the Memorial, Bay Hill or the Colonial.

Monahan practically pleaded with the organizers of the majors to reconsider their stances on the LIV players.

“How they’re going to continue to look at this current situation, the current environment, that’s up to them,” he said. “To compete in those championships you need to compete against the best, you need to compete for relevancy, you need to compete for context. And the best way to prepare is on the PGA Tour.”

Wednesday’s changes likely were well received by the Tour’s top players. But they also are a tacit admission from the PGA Tour that the league knows it could be in big trouble.