Many others in baseball noticed, too. They wanted to know about the makeup of that infield, how it could withstand so much rain, why it remained playable. The secret, they would learn with some bemusement, was a dry rock found near Slippery Rock, Pa.
It was, more precisely, a hard and powerfully absorbent clay mined, refined and sold by a small company on the outskirts of this college town 50 miles north of Pittsburgh.
Spreading the dirt
A decade ago, the Phillies, who three years earlier had been the firm's initial big-league client, were one of just a few MLB teams using Dura Edge Inc.'s products.
But Upton's soggy steal ignited a trend that has resulted in a more scientific approach to infield construction and maintenance and in Dura Edge's becoming MLB's chief supplier of dirt. Eighteen teams play on full Dura Edge infields this season. Overall, 22 use its products on warning tracks, mounds and batter's boxes.
When the Padres and Dodgers met earlier this month in Monterey, Mexico, they played on a Dura Edge infield. The 19-year-old company also has installed its infields in Europe and Asia and for nearly 1,500 American colleges, high schools and Little Leagues.
"People have no idea that most of the dirt beneath major leaguers' feet comes from Slippery Rock," said Grant McKnight, 46, the company's founder and president. "That one play in the World Series put us on the map."
While the source of major-league talent has trended ever further South, many of the game's grittier resources continue to come from a relatively tiny geographic swatch of the Northeast.
Until a recent insect infestation decimated its ash-tree population, the forest straddling the Pennsylvania-New York border provided almost all the wood for big-league bats. A South Jersey creek remains the source for mud that's used to rub up baseballs. And now a Western Pennsylvania clay is the sport's dirt of choice.
"This clay is special," McKnight said. "Every team is concerned about moisture management, and after that World Series, they all were eager to learn how it held that infield together."
Historically, MLB infields were formed from locally sourced soil or the red clays indigenous to Southern states. Though some drained or bonded better than others and almost all were slippery when wet, little serious thought was given to the dirt surfaces.
Few cared about the infield's chemical composition. Aesthetics were often as important as playability. When the Pirates were building PNC Park's infield, for example, their primary aim was to color-coordinate with the ballpark's bricks.
"I said, 'Whoa, if you're picking an infield based on color, you're using the wrong criteria,' " McKnight said.
But as the multibillion-dollar baseball industry increasingly turned to analytics and science, quality control and consistency became imperatives. Subpar dirt surfaces, it came to be understood, could lead to injuries, bad hops, delays and costly postponements. So McKnight and the game's groundskeepers ramped up the research.
From Grove City to the big leagues
The story of how this company, whose modest business offices are in an old five-and-dime store in a neighboring college town, Grove City, Pa., won a reputation and customers began in 2000. That's when Slippery Rock University asked McKnight for help with a new ballfield.
A Bucknell business grad and Slippery Rock native, the sandy-haired father of four had worked in his father's construction-materials business.
"I'd found that I loved the science of it, so I immersed myself in studying and selling sand," he said.
McKnight started his business in 1999, the height of the golf boom, and developed sand and soil mixes for courses. He applied those principles to Slippery Rock's infield and, he said, "the rest is history."
"What I'd been doing with golf greens, I started doing to infields," he said. "Then I went looking for a source of clay and found this stuff."
Mined in an undisclosed Butler County location, the clay has adhesive qualities and absorbency that make it unique.
"I went looking for a clay, and when I found this stuff, I thought it was too hard. I almost scrapped the whole thing," McKnight said. "But when I decided to mix in some sand, everything changed."
Some groundskeepers have tried to break down its chemical composition and reproduce a clay product that mimics it.
"People have tweaked local clay to get the same analytical levels. Then they put it on their infields, and it just didn't perform the same," Boekholder said. "The bottom line is they've just got better clay than everybody else."
Still, particularly at the cash-strapped lower levels of the game, the experimenting continues. That's because while Dura Edge products can cost as much as $70 a ton, a local clay might be had for $20.
The materials for an MLB-quality Dura Edge infield might go for $45,000-$50,000, McKnight said, and with minor annual maintenance could last seven to 10 years. A Little League field, he said, might cost $15,000.
"We try to get people to understand the benefits of using something that's specifically engineered to sit in a 2- or 3-inch column on your infield versus something you just pull out of the ground," McKnight said. "MLB guys understand the science, but you talk to Division I ADs and they have no idea."
In the minors; then, a call-up
In 2002, a minor-league team near Pittsburgh became Dura Edge's first professional baseball client. Three years later, the company broke into MLB with the Phillies.
At Citizens Bank Park's 2004 opening, its infield's base was a red-orange clay from Alabama, a substance Boekholder had used in his previous job at Triple-A Indianapolis. But by 2005, Phillies players were complaining about its "chipping" — breaking into tiny chunks. They wanted a substance that held together better, one that, as first baseman Jim Thome said, "was stickier."
"We started talking to our infielders, and we decided we needed more clay in the mix," Boekholder said. "That's not the easiest thing to do. Finding a source of raw clay that's not going to throw things off can be a challenge."
Boekholder remembered an unusual mound clay among the Dura Edge products the Phillies had rejected when CBP was being constructed. He phoned McKnight.
"I told him we needed 25 tons," Boekholder said. "He wanted to know if we were rebuilding our mounds. I said, 'No, I'm going to till it into my infield.' "
McKnight and Boekholder analyzed the existing Alabama clay's properties and added a percentage of Dura Edge's clay. Crews mixed it and the new surface material — which Dura Edge now markets as Field Saver — was laid down during the '05 All-Star break.
When the Phillies returned from the break, they immediately noticed a difference.
"Chase Utley asked me if we'd done something new to the infield," Boekholder recalled. "I told him we had. He said, 'This is great. It doesn't tear up at all. It's just making cleat marks. I've never seen anything like it.' "
Dura Edge's research has been done in the big leagues, the most successful processes then borrowed by minor- and independent-league teams.
"We started at the top and worked our way down," McKnight said.
At Citizens Bank Park, approximately six inches of the soil mix rest atop the field's sand base, deep enough to allow for occasional tilling.
"We don't want to take a chance of hitting the sand layer when we till," Boekholder said. "It makes it easier maintenance-wise."
In a typical year, the Phillies might use 25 tons of infield mix, 25-50 tons of warning-track dirt, 7-10 tons of mound clay, 20-22 tons of conditioning products, and 4-6 tons of the quick-drying material spread during and after in-game rainfalls.
Various means of travel
An old asphalt-manufacturing plant outside Slippery Rock is where Dura Edge mills its magic clay into a fine powder and produces its array of baseball dirt. Most MLB teams work with the firm to create their own blends.
"Anything that's not green grass is our concern," McKnight said.
At the low-slung buildings where a handful of Dura Edge workers refine and package products stand imposing piles of dirt and gravel. One pile might be a grayish dirt for big-league warning tracks; another, a high-school infield variety. Pallets hold bags filled with top-dressing, quick-dry substances or bricks of mound clay.
Some of the dirt is hauled by truck to Dura Edge's Utah facility. Some travels by railcar. And some is sent to Pittsburgh, where it's loaded onto river barges and shipped to facilities as far away as Houston.
McKnight developed the plant's production technology, a Rube Goldberg-esque system of extruding devices, belt feeders, a 70-year-old pug mill, and an ancient computer system.
As demand has increased, Dura Edge has added satellite production facilities across the country — one is due soon in the Philadelphia area. When raw clay is shipped to those sites, one of the company's portable mixers travels there to blend it with locally sourced sand and silt.
"Our clay is like Coca-Cola's syrup," McKnight said. "That stuff is shipped everywhere, mixed with local water and bottled. We ship the clay to our plants. They then use sand that's available in those places. That allows for the kind of consistent products that MLB teams want."
Because the main ingredient, the base clay, remains the same regardless of location, baseball gets the kind of uniformity it wants.
"They mix these products nationwide, so you get the exact same stuff whether you're the Salt Lake Bees or the Philadelphia Phillies," Boekholder said.
And for that, all of baseball can thank Upton's stolen base.
"When we peeled off the tarp the next morning," Boekholder said, "we scraped off the conditioner we'd put on the night before and we could have played a game by noon that day. It's the craziest thing I'd ever seen. This stuff really has changed the way we manage our infield."