None of the leaders had as shaky a stretch as Casey, who made 8 on the par-5 14th hole - after hitting into the fescue and almost whiffing on his swing to get out - and bogeyed the next hole. World number one and defending champion Dustin Johnson is among the late starters and will have to improve on Thursday's three-over effort if he hopes to take his title defence into the weekend.
"I wish I was about 5 shots better", Stricker said Friday at Erin Hills Golf Club. "But I played pretty well".
First-round leader Rickie Fowler is one shot back and tied with Jamie Lovemark and J.B. Holmes.
Fowler started on the back nine and sank birdies on Nos.
Paul Casey's birdie run is over. They were joined by Harman and Fleetwood, who each had a 70.
"It was a good display, all my own fault, of what can happen if you get out of position on this golf course, which is what I did on 14", said 14th-ranked Casey.
On that occasion Arnold Palmer, Gary Player, Hale Irwin and Ray Floyd shared the halfway lead, with Irwin going on to win the "Massacre at Winged Foot" on seven over par. He'll have a great shot at his first major this weekend. It didn't matter at that point because I was so far from the cut line, but at least I know it's in there, it's just a matter of getting it out of me and getting myself in the right frame of mind.
"I'm playing the weekend", Fowler said.
Unfortunately for McIlroy, he might well be doing just that on Friday afternoon, the 28-year-old following an eagle on the second - where he drove the green on the 330-yard par four - with four bogeys and double bogeys on the 15th and 17th.
Friday wasn't almost as favorable for the world's three-top ranked players, none of whom will move onto the weekend.
McIlroy took four of them, including a near ace on the finishing par-three ninth, to finish the tournament on five under, which will miss the cut by two or three shots.
One day later, it looked like more of the same as he went out in 34 and extended his bogey-free streak to 27 holes.
Casey finished his wild day with six straight pars for a 1-under 71 to set the target Friday. On the 12th tee, they told him he might be penalized and he played the final seven holes not knowing how big his lead was.
American Justin Thomas led a charge by early starters up the U.S. Open leaderboard on Saturday, grabbing a share of the third round lead.
However, while the world's top three are making other plans for the weekend after missing the cut, college amateur Cameron Champ is proving that massive tee shots can still help get the job done on the long, links-style layout.
Said Johnson, who was 3 over: "I really like this golf course, it sets up well for me". "But as we all know, this game's all about putting. So it's pretty simple".
"It's all good holing the putts on the practice green, but it's a different kettle of fish when you get out on the course and have to read slope, read downhill, uphill into the green, side green".
Matsuyama vaulted into contention at the U.S. Open with a 7-under 65 on Friday, moving to 5 under and a tie for eighth - just two shots back of the four-way tie atop the crowded leaderboard.