Because of this, scoring is expected to be among the lowest in U.S. Open history. Sportsbook.com lists an over/under of 270.5 (9.5 under par) on the winning score. Just once has a U.S. Open participant posted a better score – Rory McIlroy’s winning 268 in 2011. 

There has been some speculation as to whether a 62, never seen in a major championship, could be shot this week. For the record, Ian Poulter and Geoff Ogilvy think not…

@ianjamespoulter @golfchannel Maybe if 11 goes underwater and we only play 17

— Geoff Ogilvy (@geoffogilvy) June 11, 2013

But a pro golfer publicly downplaying scoring conditions is as common as a newly-hired college basketball coach touting his up-tempo offense.

The good thing about this year’s U.S. Open is that scoring is expected to resemble a typical PGA Tour event. So instead of taking Poults’ word for it, we can get a handle on the chances of a low number by looking at recent history. For instance, for all PGA Tour events with a field of at least 100 golfers since the beginning of last season, the average winning score was 270.3, very close to Sportsbook’s line. In 20 of those 58 tournaments, a score of 62 or lower was shot by somebody in the field. A 63 has happened in just three previous U.S. Opens, but just over half (30) of PGA events over the past two seasons.

Winning scores on tour are not normally-distributed, however - the distribution is skewed towards lower figures. This season’s Sony Open and Phoenix Open were both won with a score of 256, which would be -24 at Merion, an unrealistic number.  If we ignore the 12 tournaments where at least ten golfers finished with a score of 270 or better, we end up with a group that has an average winning score of 272.1. The tenth-place golfer in these events had an average score of 278.6. Of these remaining 46 tournaments, eight (or 17%) had a score of 62 or less posted at some point. Eighteen (or 39%) featured a score of 63 or less. A record score might not be so far-fetched.

However, there’s some reason to be more cautious than that analysis suggests. The 2011 U.S. Open at Congressional Country Club set the standard for low scoring at a U.S. Open. McIlroy posted that 268 and 14 golfers shot better than 280. But no golfer carded a 63 and there wasn’t even a 64 in the event.

The last time the U.S. Open was played at Merion was in 1981 and David Graham posted a winning score of 273 (-7). The only score of 65 or less in that year’s event was Ben Crenshaw’s third-round 64. And of the PGA tournaments over the past two seasons, just twice was a 62 shot in a tournament where the tenth-place golfer shot 276 (-4 on a par 70) or worse, representing 32 events. Both of those cases involved a tournament that used multiple courses, with the sub-63’s shot on the easiest course. So while scoring conditions as Merion will be easy by the USGA’s standards, it will probably take even lower scoring than expected to produce a magical 62.

But on the flip side, the winning score (even if we could know that right now) isn’t a perfect predictor of the best round score, either. The previous U.S. Opens with a 63 involved final winning scores of 279 (1973), 272 (1980), and 272 (2003). The 2009 U.S. Open featured a winning score of 276, but soggy conditions for the first two rounds allowed a pair of 64’s to be shot anyway.

Despite Poulter’s protests, a 63 is a distinct possibility this week, especially if a dozen or so players finish under par. And while a 62 is a longshot, conditions are as favorable for one as they’ve ever been at a U.S. Open.

However, barely playable is probably an accurate description of what the pros are facing this week. Several players withdrew earlier in the week, with Ian Poulter being the most transparent about his reasoning. On Friday, Sergio Garcia chipped on what would have normally been a six-foot putt due to some irregularities in his path. (ShotLink actually recorded Justin Hicks as missing a 7-inch putt while recording a double-bogey on the seventh hole yesterday, but I’m chalking that measurement up to a glitch.)

The poor conditions are apparent in the numbers as well. For instance, at last week’s Zurich Classic in New Orleans, players missed a total of six two-foot putts during the four rounds of play. Through two rounds of the Wells Fargo, players had already missed 27 two-footers. And the putting woes extend to all distances. The following graph illustrates the make percentage for golfers at each distance out to 30 feet for each of the last two PGA tournaments.

At virtually every distance out to 30 feet, fewer putts are rolling in. Two-footers are normally virtual tap-ins for the pros - at the Zurich, just 0.3% of those attempts were missed. Through Friday’s action, 2.2% of two-footers had been missed, making it something less than a formality. Three-footers that were missed at a 2.9% rate at New Orleans are being missed at a 8.2% rate at Charlotte. Longer putts have become more of a prayer, too. At the Zurich, 11.3% of putts between 20 and 30 feet went in the hole. So far at Quail Hollow, just 6.4% of those putts have dropped.

But is any of this significant? After all, we are talking about what some people are describing as the worst greens seen on tour in many years. What does that mean in professional golfing terms? One way to think about it is that players are getting a 20-30% distance penalty on the greens. Accuracy from three feet at Quail Hollow is roughly what it was from four feet at the Zurich. A 20-foot putt is going in at the rate of a 27-footer at the Zurich. (This isn’t a perfect translation, of course. For some reason there is less of a penalty in the 6-8 foot range.)

I don’t know if that’s a big difference or not, but I do know that Phil Mickelson has been largely unaffected by this reality. I don’t think it’s hyperbole to say the last two days have been some of the best putting of Mickelson’s life. Golf analytics is in such a state that we can’t know this for sure. It’s also in a state that the people covering the event this week are probably wholly unaware of what he’s accomplished. And I’m guessing if anyone asked Phil, he’d probably laugh at my statement. However, here’s a summary of his life on the greens in the first two rounds.

Rd Hole  1st Putt  In?  2nd Putt
 1  10     7'5"     Y  
 1  11     7'5"     Y  
 1  12     4'5"     Y  
 1  13    13'11"    Y  
 1  14     3'2"     Y  
 1  15    14'8"     N     0'9"
 1  16     8'7"     Y  
 1  17    34'7"     N     0'8"
 1  18    18'1"     N     1'7"
 1   1     9'2"     Y  
 1   2    17'4"     N     2'0"
 1   3    34'9"     N     2'0"
 1   4     7'5"     Y  
 1   5     6'1"     Y  
 1   6     2'11"    Y  
 1   7    49'0"     N     2'8"
 1   8    12'11"    N     1'6"
 1   9    19'0"     Y  

 2   1    13'6"     Y  
 2   2    14'5"     Y  
 2   3    47'11"    N     4'5"
 2   4     2'2"     Y  
 2   5    15'1"     N     0'11"
 2   6     2'8"     Y  
 2   7     9'5"     Y  
 2   8     0'10"    Y  
 2   9    39'3"     Y  
 2  10     3'9"     Y  
 2  11    18'5"     N     1'6"
 2  12    11'1"     N     1'3"
 2  13    23'11"    N     1'8"
 2  14     5'0"     Y  
 2  15     1'6"     Y  
 2  16    19'3"     N     1'3"
 2  17     6'7"     Y  
 2  18    11'11"    N     0'10"

Phil’s driving and approach game this week has been eminently cuttable. With average short game and putting he wouldn’t be seeing the weekend, let alone hanging around the top of the leaderboard. The PGA Tour uses a stat called strokes gained to measure putting performance. It tells you how many strokes a player has gained on the field through his putting. In the first two rounds, Phil gained 9.4 shots on the field with his putting and he his score of 9-under was 12 shots better than the cut line. Throw in a really good short game this week and you can see that the difference between a weekend off and a two-shot lead can be attributed solely to his work around and on the green.

He’s rolled in five putts of more than ten feet and another seven of at least six feet. Normally, this is a great week, but on a course where all of these putts are playing longer, it’s incredible. His shortest miss has been from 11’1”. In addition, something that strokes gained doesn’t capture is that he hasn’t left himself any work for the second putt. In a normal week that isn’t a big deal. But with two, three and four-footers being missed with increasing regularity, the close misses have been another reason for Phil’s success.

Mickelson has mentioned that on the slower-than-normal greens he’s able to be more aggressive with longer putts, but that hasn’t been the case for the rest of the field, as three-putt rate is significantly higher over last week as well. On putts of 35 to 45 feet, pros are three-putting 15% of the time this week compared to 8% last week.

Obviously, Mickelson’s level of putting is unsustainable. Unfortunately, the PGA’s stats page doesn’t give a lot of context for Phil’s performance over the first two days but we do know that Phil’s strokes gained on the green through two rounds is better than the best putters for four rounds in most tournaments last season. So you’d have think that the putter will cool off and if Phil wins the tournament the tee-to-near-green game will have improved substantially over the weekend. If he does continue to putt well, it’ll be highly unlikely he’s ever had a week on the greens like this one.

On the flip side, however, the other par 5 on the back nine, number 15, was the worst test of a golfer’s skill. Augusta National uses “par 5” advisedly here since the average score on the hole was closer to 4 than 5 on Thursday. Basically, it played like a par 4. Ten golfers eagled it and finished with an average score of 73.2. The 43 players that birdied it finished with an average score of 72.7. The 37 golfers that parred it finished with an average of 73.4. Even the three players that bogeyed it ended up averaging 73.3. If you camped out at 15 all day, you saw some of the world’s best players but you also could not have drawn any conclusions on a golfer’s ability based on what you saw. All told, the R² for a player’s score on 15 and their final score was 0.05.

Of course, this is probably just statistical noise. I wouldn’t expect 13 to hold up as the single-most significant hole through each day of the tournament, except for the possibility that it’s a par 5 and there are more chances for a golfer to show his skill there. Still, that effect must be somewhat small.

The 13th hole also featured the most variance among individual scores. The standard deviation of scores was 0.81, with one eagle, 38 birdies, 40 pars, 12 bogies, one double bogey, and one triple bogey. The least interesting hole was the par-3 fourth with a standard deviation of 0.47. It saw nothing but pars except for two birdies and 23 bogies.

In terms of players, the award for the most interesting scorecard goes to Craig Stadler. En route to a 7-over 79, he carded three birdies, four bogeys, a double, and a quad. The least interesting scorecard was turned in by Fredrik Jacobsen, who finished at even par after a round with a birdie, a bogey, and 16 pars.