It's just that people pay more attention now.
That's the burden of winning more majors than Tiger Woods over the past two years.
Harrington took his place in the record books last summer as the first European in more than a century to win the British Open in consecutive years, and the first European to win two majors in a row in the same season.
And what has he done since?
Only twice in his past 21 tournaments has he finished in the top 10 -- Singapore and in Abu Dhabi. He has yet to crack the top 20 in his dozen starts on the PGA Tour this year, missing the cut in half of them.
Harrington arrived at Bethpage Black for the U.S. Open on Saturday after another short week at the St. Jude Classic, the third consecutive tournament in which he missed the cut.
Some players are sensitive to slumps, saying the scores don't reflect how well they're hitting the ball.
Count Harrington among the honest ones.
"I think the results are very much a reflection of how I've played," he said Tuesday. "I haven't played very well, and certainly haven't made things happen."
Not that he hasn't tried.
Harrington is the hardest-working man in golf, even though Vijay Singh gets all the credit. The Irishman will practice in any weather at any time of the day, not because he has nothing better to do, but because he's always trying to improve.
"I don't hit that many balls," Geoff Ogilvy said. "But I haven't been on a range this year that he hasn't been on."
Some believe that's what has led to such an atrocious start to the season for Harrington. He is constantly tinkering with his swing, which wouldn't seem to make much sense because the old swing worked out all right.
"The way to get better is improve things and change things," Harrington said. "And if that means I step back a bit, that's OK in the short term. I would have liked to have come out just a little quicker, and certainly, I didn't intend to drag it so far into the season. But some of these are just ..."
Then he paused to smile.
"The road to hell is paved with good intentions," he said. "I did have good intentions. I'm comfortable with it. I'm going to be patient. I know where I am. That's very important. I do actually know where I am in my game."
Whether that's enough to handle Bethpage Black isn't something he can answer at the moment. But he's not about to panic.
Harrington has been tinkering as long as he has been playing golf. It's not unusual for him to reach a new plateau, then take a tumble backward as he tries to keep climbing.
"There has been a bit of focus on work I have been doing on my swing," he said. "In fairness, I've done that work all the time at different stages in my career. The difference is I'm a little bit more high-profile now, and the spotlight is on me."
It will shine even brighter Thursday. He will play the first two rounds with Masters Tournament champion Angel Cabrera and Woods, the defending U.S. Open champion.
In a search for answers, someone asked Woods why someone would change a swing that won a major or three.
"You're asking the wrong guy," he said. "After I won the Masters by 12 (shots), I changed my swing. People thought I was crazy for that. I said, 'Just wait. Just be patient with it. It will come around.' "
Did it ever. He won 17 times over the next two seasons, and capped off that overhaul by winning four consecutive majors.
"Sometimes you have to take a step or two back before you can make a giant leap forward," Woods said. "And that's the hard part, sticking through those periods."
Ogilvy used to lose his temper, if not his mind, if his game deserted him for a couple of holes. He understands the frustration of hitting balls for hours on the range without feeling instant gratification.
Harrington is a different breed.
"Most of the guys would get depressed if they won two majors and started struggling," Ogilvy said. "But he seems to be to just say, 'It will be all right. I'm working it out. It's a project of mine. When I work it out, we'll get back to winning tournaments.' ... And not many people can do that."
That will be the case Thursday, no matter how he plays. Harrington concedes his confidence level is not where it was at Oakland Hills last August, when he won the PGA Championship. How can it be after missing three cuts in a row?
"As we say at home," he said, "the lightning storm is too late to get up and patch the roof. So I've got to accept that I've got this week."