BROOKLINE, Mass. — USGA CEO Mike Whan said the governing body felt it was appropriate to allow players who were suspended by the PGA Tour for competing in the rival LIV Golf Invitational Series to play in this week’s U.S. Open, but he added that he could foresee a day when it’s more difficult for them to qualify.

Whan, speaking at a news conference on Wednesday at The Country Club outside Boston, said the USGA will continue to monitor the professional golf landscape while evaluating its qualifying criteria for future U.S. Open tournaments.

“I could foresee a day,” Whan said. “Do I know what that day looks like? No, I don’t. To be honest with you, what we’re talking about [LIV Golf] was different two years ago, and it was different two months ago than it is today. We’ve been doing this for 127 years, so I think [the USGA] needs to take a long-term view of this and see where these things go. So we’re not going to be a knee-jerk reaction to kind of what we do.”

On Thursday, PGA Tour commissioner Jay Monahan indefinitely suspended 17 players for competing in LIV Golf’s inaugural event outside London. The players included past U.S. Open winners Dustin Johnson, Martin Kaymer and Graeme McDowell. Monahan said the players were punished for competing in a rival circuit without a conflicting-event release. The first LIV Golf event coincided with the RBC Canadian Open in Ontario.

Seven of those players, including Johnson, Louis Oosthuizen, Sergio Garcia and Phil Mickelson, are competing in the U.S. Open this week.

Two other players — 2018 Masters champion Patrick Reed and 2020 U.S. Open winner Bryson DeChambeau — have also announced they’re joining LIV Golf and plan to play in its first event in the United States, which is scheduled at Pumpkin Ridge in Portland, Oregon, from June 30 to July 2.

A LIV Golf spokesperson told ESPN that the full field for the Portland event would be released next week.

“Listen, I’m saddened by what’s happening in the professional game,” Whan said. “Mostly as a fan because I like watching the best players in the world come together and play, and this is going to fracture that. I’ve heard that this is good for the game. At least from my outside view right now, it looks like it’s good for a few folks playing the game, but I’m struggling with how this is good for the game.”

A former LPGA commissioner, Whan said he liked that golf was the only professional sport controlled by its players. While Monahan serves as commissioner, the Player Advisory Council has much influence in PGA Tour decisions.

The LIV Golf series, which is being fronted by two-time Open champion Greg Norman, is being financed by Saudi Arabia’s Public Investment Fund.

“I would walk into a board meeting at the LPGA, and it was players on the board,” Whan said. “They didn’t report to a bunch of owners. They didn’t report to two guys that had all the money and had all the decisions, and if those two guys changed their mind, we all had to change our plans. Professional golf has been for a long time their sport. Not a couple of people’s sport.

“What concerns me or saddens me the most is we could get to the point where a couple of people hold those strings, and how they act may or may not be great for the game. I don’t know.”

Whan said Monahan hasn’t tried to influence the USGA to change its qualifying requirements to make it more difficult for LIV Golf players to get into future fields.

“We definitely feel responsibility to this game, and we feel a responsibility to the competitors that play it,” Whan said. “We did sit down and have a long conversation about a week before the U.S. Open. [We asked ourselves], ‘Did where somebody else play and what promoter they played it with disqualify them for this event?’ We decided no on that, with all the awareness that not everyone would agree with that decision.”

Going down that route, according to Whan, would require the USGA to examine the playing history of more than 9,300 people who tried to qualify for the U.S. Open.

“It becomes a pretty slippery slope to try to apply that across 9,300 people,” he said.

On Tuesday, four-time major champion Brooks Koepka said he was upset that the LIV Golf debate was casting a “black cloud” over the U.S. Open. He isn’t alone.

“We’re praying that that changes [when play starts on Thursday],” Whan said. “Even I can say that you don’t have to ask how we feel about it. Ask 156 players that are grinding it out out there to get to tomorrow.”