Back in 2019, Rory McIlroy began his Open Championship with a tee shot that found the internal out of bounds on Royal Portrush’s opening hole, eventually carding a first-round 79 and later missing the cut.

Four years later, internal out of bounds has returned at the sport’s oldest major and could factor again, potentially on the final hole of this year’s Open at Royal Liverpool.

The white stakes and lines guard the third and 18th fairways from what is usually the members’ practice range; this week that land, which is guarded by a short, stone wall, houses championship infrastructure, including hospitality and merchandise tents. The out of bounds comes into play at the par-4 third, normally the members’ opening hole, off the tee, where players will try to cut off the right dogleg over the wall, and on the approach, as the out of bounds line sits just a few paces off the right side of the green. But it’s the par-5 finishing hole, the members’ 16th, where the internal out of bounds could prove more impactful.

The last time the Open came to Hoylake, in 2014, a similar internal out of bounds was used. No. 18, with out of bounds up nearly the entire right side, played 0.2 shots under par, yielding nine eagles, yet 26 scores of double bogey or worse were recorded, which was six more than any other par-5 on Tour that year.

This week, even those numbers could skyrocket as the internal out of bounds has shifted about 20 yards left, toward the fairway and away from the stone wall. There is a new back tee, too, 50 yards longer than nine years ago. Plus, a bailout left risks finding one of several dangerous pot bunkers, which are a “no-no,” according to head pro John Heggarty, who adds this of No. 18, “The tee shot is now parallel to the out of bounds, so that gives you a better perspective, but the fact it has come in 20 yards does mean that the fairway’s narrower.”

Matthew Jordan, a competitor in this week’s field but also a Hoylake member since age 7, loves the added difficulty to No. 18.

“In terms of 18 bringing the out of bounds in, I think it's a lot better,” Jordan said. “I think it makes it a proper risk and reward hole. If you hit a good drive, you can go for it. Then even bailing out on the left, it makes the lay-up a lot tougher because it's a bit longer now. I think certainly from my opinion 18 especially has been a brilliant change.”

Brooks Koepka was also asked about the challenge.

“It’s fine,” Koepka responded. “Just don't hit it over there you won't have a problem, right?”