Jon Rahm hopes the Ryder Cup “does not suffer” if more players join the new Saudi Arabian-funded LIV Golf series.

The Spaniard is defending his US Open title at Brookline this week, the scene of a memorable United States victory against Europe in the 1999 Ryder Cup.

The world number two said: “The Ryder Cup is the biggest attraction the game has to bring new people in.

“I hope we don’t lose the essence and the aspect that the Ryder Cup is. That’s one of my biggest concerns.”

The 27-year-old added: “It’s an event we all play for free, and it’s one of our favourite weeks, win or lose. I think that says a lot about the game and where I wish it would be at.”

European players need to be a member of the DP World Tour to be eligible to play in the biennial event, which will next be contested in Rome in September 2023, while Americans need to be members of the PGA Tour.

PGA of America chief executive Seth Waugh said last year: “If someone wants to play on a Ryder Cup for the US, they’re going to need to be a member of the PGA of America and they get that membership through being a member of the (PGA) Tour.”

However, the PGA Tour has suspended all of its members that have played, or signed up to play, in LIV Golf events.

Meanwhile, the DP World Tour issued a memo to its players on Tuesday saying “because of the complexity of the situation we are still evaluating an overall course of action”.

The note, sent by chief executive Keith Pelley, said they will “use the next seven days to assess the impact the two conflicting events (LIV Golf event and Asian Tour event held the week before in Northumberland) had on our tournaments played in those weeks”.

A decision from the DP World Tour – the branded version of the European Tour – is expected on 23 June.

Americans Bryson DeChambeau and Dustin Johnson, who both played in the record 19-9 victory at Whistling Straits last September, are among those to join LIV Golf.

Patrick Reed, who played in three editions between 2014 and 2018, will play in the second event.

On the European side, Ryder Cup stalwarts Ian Poulter, Lee Westwood and Sergio Garcia have also defected to the start-up circuit.

“Are they going to be able to play Ryder Cup or not, the players that went?” asked Rahm.

“In my mind, Sergio, even if he is not breaking 90, he’s a no-brainer pick, right? So what’s going to happen?

“You have quite a few young Americans. Bryson went, somebody that’s probably going to be on the team in the future. Phil’s [Mickelson] captaincy is probably in question now.

“I have no idea what’s going on or what’s going on with the European Tour. I don’t know what’s going to happen.”

Rahm played a practice round with LIV Golf defectors Mickelson and Kevin Na on Tuesday but said he had no desire to join them on the new circuit.

“Part of the format is not really appealing to me,” he said. “Shotgun [start] three days to me is not a golf tournament, no cut. It’s that simple.”

And while he accepted some players would join the £200m eight-event series, which has a further £1.6bn pot to turn it into a proper league by 2024, Rahm said there is more to the game than money.

“I do see some of the, I’ll put this delicately, points or arguments they can make towards why they prefer it,” he said.

“I want to play against the best in the world in a format that’s been going on for hundreds of years.

“I’ve always been interested in history and legacy, and right now the PGA Tour has that. My heart is with the PGA Tour.

“I could retire right now with what I’ve made and live a very happy life. When [my wife] Kelley and I started talking about it we were like, will our lifestyle change if I got $400 million? No, it will not change one bit.

“I play for the love of the game, and I want to play against the best in the world.”