Willett, who pulled out before the start of his second round, was heading towards the Erin Hills exit anyway after slumping to an opening round nine-over 81.
Koepka, playing the back nine first, birdied four of his first seven holes.
Uihlein made three consecutive birdies from holes No. 11-No. "I had to hit it all". But the former Irish Open victor posted one under for the back nine to get into the clubhouse just inside the cut mark. There were five players in double digits Saturday at Erin Hills. He hammered a chip from just short of the par-5 14th that led to another three-putt bogey. Pat Perez swung and missed completely in the tall grass behind the 15th green. "I took advantage of it the last few days". It didn't get any better when he finally made the green.
The top three golfers in the world, and six of the top 10, didn't make it.
Casey, the former world No 3, has always possessed so much talent that it is, in fact, a surprise that he has not figured at the business end of more majors.
With Fowler not teeing off until the afternoon, the morning action was dominated by a roller coaster round from England's Paul Casey, who recovered from a dramatic collapse to claw his way back into contention.
The lead, however, belonged to Brian Harman. No other information was provided.
The biggest surprise at this U.S. Open was not who was leading, but who was leaving.
It sounds as if Erin Hills is becoming more challenging with each passing minute. The 28-year-old's seven-under-par total matched the lowest to par score ever carded in the opening round of a US Open, a record shared by Jack Nicklaus and Tom Weiskopf since the 1980 tournament. "And I just unfortunately didn't execute". I think the more rounds I can play, I'm hopefully going to get rid of all that stuff and hopefully strip it down to what you saw the last six holes.
Harris English is 4 under after a second-round 69.
In the final round at Oakmont previous year, his golf ball moved slightly as he positioned himself for a short putt on the fifth hole. Harman was at 12-under 204 and still only had a one-shot lead, with Rickie Fowler two shots behind. McIlroy came to life when it was far too late. He just missed an eagle at the par-5 seventh after a long putt rolled just wide of the cup. He shot 68 and was only three back. This one he'd rather forget. His drive appeared to sail into the rough. It took a hard turn to the right and rolled in.
Fowler wasted no time in exploiting the conditions after teeing off on the 10th, rattling off four quick birdies to be four under.
It was day of sizzling drama on the links-style layout that featured stunning birdie runs and spectacular collapses - some like Casey coming on the same scorecard. He tapped in for par. He had reason to smile he's tied for the lead. This is his third try at the U.S. Open and the first time he has made the cut.
OK, this is his first U.S. Open.
Here comes Si Woo Kim.
"It's going to be great", said Fleetwood, a 26-year-old Englishman who won at Abu Dhabi on the European Tour earlier this year.
One shot back. Jamie Lovemark. But that wasn't the problem.
His problems deepened at the par-four 12th, when his second shot rolled off the back of the green. It's just, concentrate on each day as it comes.
Rory McIlroy finished his second round with a string of birdies, however, the world number two also missed the cut.
Thomas became the fifth player to shoot 63 in the U.S. Open, and the first with a score of 9 under.
Casey refused to let the triple get him down and accepted accountability.
The top 60 and ties make the cut at the U.S. Open.