Since then he hasn't finished higher than 25th at any major (last year's British Open), and in April he tied for 40th at the Masters. But at least he played the full 72 holes. Not this time.
McIlroy, who threw out the first pitch across town at the Giants game on Tuesday night, shot a 3-over-par 73 Friday at the Olympic Club. It was 4 better than he'd carded in the first round, but it still wasn't good enough to get him into the top 60. So he's heading home early, like a bunch of others. But most of them aren't ranked No. 2 on the global food chain.
"It wasn't the way I wanted to play," said McIlroy, who had three birdies and 13 bogeys in 36 holes. "I left myself with a lot of work to do after [Thursday], and to be honest overall I don't feel that I played that badly the last two days. It's just such a demanding golf course and just punishes the slightest shot that's off line or that's maybe not the right distance or whatever, and that's how I feel. You really have to be so precise out there."
It's a major; it's not supposed to be forgiving. That's why they call this major the game's most scrutinizing examination, right?
"We're just not used to playing this sort of golf course week in, week out," said McIlroy, who was 10th in 2009 at a very demanding, albeit rather waterlogged, Bethpage Black in his other U.S. Open appearance. "You have to adapt and you have to adjust. And I wasn't able to do that very well this week.
"The thing about the U.S. Open is you got to hit it in the fairway, and you got to hit it on the green. So it's something I needed to do a little more often in this tournament," he said. "I know I needed a few birdies coming in today, so I just tried to attack as much as I could and go for pins. I thought I might have a chance to make the cut. But once I missed [a good birdie look at No. 8, his last hole], I knew that I probably wouldn't.
"But as I said, I felt like I had some good shots out there, and I don't think the score [150, two off the cut line] that's on the board really reflects how I played."
He wasn't the only European big-timer who struggled. In fact, he had to look no further than his own threesome. Luke Donald, the world No. 1, also missed the cut by going 79-72, which means he's still lacking a major title. Lee Westwood knows the feeling, but at 145 (73-72) at least he can still, perhaps, rectify that.
If nothing else, it's certainly a fickle game. The good news is, McIlroy's probably got another two decades or so left out here. The British Open is a month away. He should still be among the favorites, unless of course he continues being a weekday-only kind of hacker. That tends to humble even the best in a hurry.
"It just makes you realize that you got to keep working hard, and you got to," McIlroy acknowledged. "It doesn't come easy to you all the time, yeah. It hasn't been the greatest run over the last sort of six weeks or whatever it is, but I still see enough good stuff that it does give me hope that it's not very far away. . . .
"That's the plan. So just go back home and start playing some links golf and get ready for [what's upcoming]."
Contact Mike Kern at kernm@phillynews.com.