This golf rule could determine the outcome of the Ryder Cup

“The one-ball rule is not in effect.”

US captain Zach Johnson casually dropped that bombshell during one of his several pre-tournament press conferences, and it could have huge implications on which lifts the Samuel Ryder trophy on Sunday.

The humble golf ball has, for many years, been a huge discussion point ahead of the Ryder Cup, with many foursomes pairings on both sides being dictated by the brand and model they use.

Who can forget the Tiger Woods-Phil Mickelson pairing in 2004? As if it wasn’t doomed enough in the build up to that year’s contest, Mickelson being forced to use Tiger Woods’ golf ball at Oakland Hills did not go down well. And then there was the infamous spat between Seve Ballesteros and Paul Azinger in 1991, when the swashbuckling Spaniard accused his rival of lying about how many times they had swapped golf balls during their match.

But it won’t be as much of an issue this week, with the model local rule not in place at Marco Simone.

The one-ball rule – or Model Local Rule G-4, as the R&A and USGA call it – “is an optional condition that committees may choose to use”.

“If this rule is in effect, you must play with the same brand, make and model of golf ball that you started the round with.”

So that means if you tee off on the first hole with a Callaway Chrome Soft, you must play the entire round with a Callaway Chrome Soft. You can’t switch to another brand – or even another model of Callaway golf ball – mid-round.

But with the rule not in play this week, it means pairings will be able to swap their golf ball from hole to hole, rather than deciding on the first tee whose ball they will use for the full match.

If you’re wondering why this matters, it’s because golfers – at that level, anyway – are incredibly particular about their golf ball, and they are dialled in to everything from compression to spin rates. It’s incredibly technical.

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Rory McIlroy explained how the players get around it in the alternate shot format.

“All these golf balls react pretty similar with a driver,” he said. “It’s more the iron shots and around the greens.

“If I’m playing with a guy that uses a different golf ball, I can just hit his golf ball off the tee, he’s able to hit it into the green, and we go from there.

“Vice versa – he can hit my golf ball off the tee, and I can hit my ball into the green.

“It can get a little tricky and you’re chipping and putting and different feels of balls.”

He then got a bit more technical. “Spin rates is a big thing, especially in the wind gets up in some of these elevations,” he said.

“If you’re into the wind and, say, the other golf ball minutes 200 or 300 RPMs more than your golf ball, that makes a huge difference. So just trying to get comfortable with that in some ways and trying to be mindful of it.

“But I don’t think it presents a huge challenge. I think guys are pretty much adaptable. We have 24 of the best players in the world here. If we can’t adapt a little bit to a slight change of the golf ball, the game is certainly not going in the right direction. So I think we are all OK.”

Alex Perry is the Associate Editor of bunkered. A journalist for more than 20 years, he has been a golf industry stalwart for the majority of his career and, in a five-year spell at ESPN, covered every sporting event you can think of. He completed his own Grand Slam at the 2023 Masters, having fallen in love with the sport at his hometown club of Okehampton and on the links of nearby Bude & North Cornwall.

Associate Editor