“Trying not to think about it too much,” he said. “Low expectations and whatever happens.”

A native of South Korea, Kim played golf at Torrey Pines High and is now a junior on the California team.  Just past 6 p.m. EDT, he was tied for fourth place.

Saturday afternoon saw several players making charges on the back nine. In addition to Kim, Jason Day moved to two over with birdies on Nos. 10 and 13.

Charl Schwartzel claims the lead at one under | 2:22 p.m.

There are two ways to miss a breaking putt.

That would be the high side of the hole or the low side, otherwise known as the “pro” side and the “amateur” side because professionals usually have the confidence to stroke the ball more firmly.

So why are players at this U.S. Open missing on the low side so often? Blame a tough course, tilted greens and the ever-changing weather over the last five days.

“When the greens are very fast like this and you have soft greens that get indentations and spikes and so forth, it’s very hard to make putts,” Phil Mickelson explained after the second round. “You can’t hit them firm enough to hold the line.”

On Saturday afternoon at Merion, Mickelson missed low on a putt to save par and Tiger Woods made the same mistake to settle for par on No. 8. Steve Stricker’s low-side miss denied him a share of first place on the same hole.

Just past 5 p.m. EDT, Charl Schwartzel held a tenuous lead at one under, with Stricker, John Senden and Luke Donald a stroke back.

Yo, Adrian: The day before the U.S. Open began, Rory McIlroy took a break from preparations to drive into nearby downtown Philadelphia. The reason for his visit? The golfer from Northern Ireland wanted to run up the 72 stone steps in front of the Philadelphia Museum of Art.

That’s where Rocky trained before his big bout with Apollo Creed.

“Can’t come to Philadelphia and not see the 'Rocky' steps!!” McIlroy tweeted.

With a Phillies cap turned around backward on his head, he paused at the top to strike Sylvester Stallone’s iconic pose, arms thrust upward. But at six strokes off the lead on Saturday afternoon, he might need the golf equivalent of a 15th-round knockout to get back into contention.

Luke Donald, John Senden take the lead | 1:25 p.m.

We’re halfway through moving day at the U.S. Open, but there hasn’t been a whole lot of movement at the treacherous Merion Golf Club.

The U.S. Open tradition of par golf -- or worse -- continued to keep the field in check, with second-round leaders Phil Mickelson and Billy Horschel shifting into reverse, dropping a stroke to stand at even.

Meanwhile, Luke Donald and John Senden transformed birdie putts into a share of the lead at a modest one under par.

Coming into the third round, Mickelson looked at the pin placements and wondered if the course was set up for a few rounds in the mid-60s. Senden certainly started out that way, playing at two under through four holes. And Edward Loar clawed his way back into contention at one over with an eagle and birdie on the front nine.

But most of the field hovered around par as alternating scenes of frustration and small triumph played out across Merion’s devilish 111 acres.