AP photo by Julio Cortez / Collin Morikawa reacts after missing a putt on the eighth hole during the second round of the U.S. Open on Friday in Brookline, Mass. Morikawa, a major champion each of the past two years, shot a 66 and shared the 36-hole lead with Joel Dahmen.

BROOKLINE, Mass. — At this week's U.S. Open, for every golfer like Collin Morikawa — the PGA Championship winner in 2020 and the British Open champion in 2021 — there is another such as Joel Dahmen, who only four years ago would have been thrilled to even play in one major championship.

Jon Rahm is the tournament's reigning champ and one shot out of the lead. He will be playing on the weekend at The Country Club with Hayden Buckley, who was a Division I golfer at Missouri but also made sure to study — because he figured after college, he'd need to find a job that didn't involve making par.

The dozen players separated by two shots going into the weekend include the top three players in the Official World Golf Ranking and four of the top seven — Masters champion Scottie Scheffler, Rahm, Rory McIlroy and Morikawa.

"I think it's great for the game of golf that the highest-ranked players and the best players are up there, especially in the tournament where truly the best player ends up winning," Rahm said.

The top 12 on the leaderboard also included two PGA Tour rookies and two players who have never won on tour.

Indeed, this U.S. Open has something for everyone. It just doesn't have Phil Mickelson, who missed the cut by eight shots.

Morikawa was searching for something in his game and found a "baby draw" instead of his traditional fade, and it's been working beautifully in Brookline. He matched the low score of this year's tourney so far with a 4-under-par 66 in Friday's second round for a share of the lead at 5-under 135 with Dahmen (68), the cancer survivor and popular everyman in golf.

Rahm did his best to keep pace with an eagle and a series of big par putts that felt just as valuable on the way to a 67. He was in the group of five players one shot behind, which included McIlroy, coming off a win at the Canadian Open and never more entertaining.

McIlroy was two holes into his round when an errant approach landed in waist-high fescue. He took a hack. And then another. The third try finally found the green, and he holed a 25-foot putt to salvage a double bogey.

McIlroy hit his stride on the back nine with three birdies over his last four holes for a 69.

"After 36 holes in a major championship, that's all you want to do is put yourself right in the mix going into the weekend," McIlroy said. "For a little part of the day there, it seemed like I was going to be a few more behind. But I dug deep and played the last eight holes really, really well."

Not to be overlooked was top-ranked Scheffler, the hottest golfer on the PGA Tour this year, who chipped in from thick rough short of the par-5 14th green for an eagle that brought the 25-year-old Texan back into the mix with a 67. He was two shots behind, tied for eighth.

Morikawa, Rahm and Scheffler have combined to win four of the past nine majors. And then there's McIlroy, who has four major championships by himself, but none since 2014.

"It's the U.S. Open. No one has taken it deep so far and kind of run away," Morikawa said. "The last few days is a huge confidence booster for me heading into this weekend, and hopefully we can kind of make some separation somehow."

The idea of the U.S. Open is to identify the best players. Some of them require some introductions to major championship contention on the weekend.

Start with Dahmen, who will never be accused of taking himself too seriously, even if he takes his game seriously. He thought about withdrawing from his 36-hole qualifier twice last week, before it started and after the first round. But he stuck it out, and now he's about to play in the final group of a major for the first time.

"We don't tee off until 3:45 tomorrow. I typically have to be home at 5 for dinner," Dahmen said. "So this will be different, for sure."

The group one shot behind includes Buckley, who wasn't in the U.S. Open until making a 20-foot birdie putt in a playoff for the last spot in his qualifier on June 6.

He was fading Friday, like so many others, with three bogeys during a five-hole stretch around the turn when he got back on track. Birdies on the last two holes gave him his second straight 68.

Also at 136 were Aaron Wise, with one PGA Tour victory and nothing better than a tie for 17th in his nine previous majors; and Beau Hossler, who made the weekend at the 2012 U.S. Open as a teenage amateur but hasn't been heard of since then in the majors.

They were examples that the U.S. Open being open to all doesn't just stop with qualifying for the right to play the toughest test in golf.

The weekend won't have Mickelson, hardly a surprise. He took a four-month hiatus related to his inflammatory remarks about the PGA Tour and the Saudi-backed league he was promoting, wound up joining LIV Golf anyway and returned to competition last week with poor results in the series' debut near London.

The U.S. Open was a slightly stronger test and Mickelson was exposed, particularly on the greens, with rounds of 78-73 to miss the cut, which was at 4 over. His next stop is Portland, Oregon, in two weeks for another LIV Golf event, and he won't have to worry about making the cut because the 54-hole event won't have one.

McIlroy never panicked after his double bogey. He took advantage of the birdie chances on the drivable par-4 fifth and the short par-5 eighth. And he finished strong to get right in the mix, his main goal going into the weekend.

Adding to the anticipation for McIlroy was seeing so many familiar names at the top.

"You want to go up against the best to try to bring the best out of yourself," McIlroy said. "And to see Collin and Jon and Scottie and Sam (Burns) up there and whoever else, that's what major championship golf is all about. That's what competition is all about.

"And that's at the heart of this game. I'm excited to be in that mix going into the weekend."

Former Baylor School standout Harris English, third at the U.S. Open last summer and fourth in 2020, will have to do some climbing to have another solid finish in the United States Golf Association's big event. He gave himself that chance by shooting a 69 that sent him to the weekend with a little wiggle room. He was tied for 40th at 2 over.

Luke List, another former Red Raiders standout who earlier this year earned his first PGA Tour victory, followed his opening 73 with a 72. This was the 37-year-old's sixth U.S. Open, but he has yet to make the cut.