The Grass Is Actually Greener Thanks to M.L.B.’s New Rules

Greg Elliott, the forward-thinking head groundskeeper for the San Francisco Giants, flies a drone over the pristine grass at Oracle Park five days a week. The device is equipped with an infrared camera that measures the stress levels and overall health of the turf. In the first two months of this season, Elliott had detected a notable difference from the previous two years.

The grass in shallow right field was not as chopped up and worn down as it had been. The same went for the rounded edge of the outfield grass that meets the infield dirt behind the shortstop and second base positions, where infielders’ spikes had previously dug in as the players awaited ground balls.

The improvement in those areas is perhaps the most surprising result of Major League Baseball’s significant rule changes for this season. The ban on defensive shifts means infielders are no longer allowed to linger in those locations, which, combined with the pitch clock, is helping to improve field conditions throughout baseball.

“They are not playing on the grass anymore,” Elliott said, “and it’s really making a positive difference.”

Long before the rule changes, Elliott and others worked to improve the process of cultivating and maintaining M.L.B.’s fields — an undertaking that has shown results in baseball’s 28 natural grass stadiums. The shimmering emerald grasses and crushed-brick top dressing on the infields had always been breathtaking, but because of technological advances, like Elliott’s drone, parks have become shrines to modern grass and dirt cultivation.

There are targeted fertilizers, designer dirts and organic pesticides. Robotic mowers work side by side with veteran groundskeepers. Fields look lusher and greener and remain so for longer periods, lending not only beauty but fairer play and uniformity from park to park.

“The materials, the tools and the equipment are all so improved, and you have better fields over the last 25 years,” Murray Cook, M.L.B.’s field coordinator, said. “Everybody has got really nice fields now.”

The Old Chicanery

With their varied surfaces and dimensions, baseball fields require some of the most meticulous care of any sports surface. For decades, grounds crews customized their fields to enhance the attributes of the home team. If your club’s pitchers induced ground balls, you might leave the grass higher to slow them down. Basepaths could be sloped toward fair territory if your team liked to bunt, or the other way if you had trouble fielding them. The pitching mounds varied, often based on the proclivities of the home team’s pitcher for that day.

Jim Palmer, a Hall of Fame pitcher for the Baltimore Orioles from 1965 to 1984, still remembers fighting with the mound at the old Tiger Stadium in Detroit. Palmer would kick and dig at it with his spikes, but the dirt in front of the pitching rubber would resist like concrete, at least for the first few innings.

“You just hoped you were still in the game by the fourth inning, when it would loosen up,” Palmer said. “Some mounds had different slopes, some were too high or too low or too loose. You had to figure it out as you went along.”

Tom Burns, a former head groundskeeper for Cleveland and the Texas Rangers, has been in the industry since 1978. He recalled the days when a groundskeeper’s main tools were a wheelbarrow and a metal rake and when managers sometimes asked the crews to tailor the field to their own preferences. Perhaps the modifications worked, but much of the time it was just gamesmanship.

Gaylord Perry, a Hall of Fame pitcher, wanted the infield grass as high as corn. Burns, who won the coveted Harry C. Gill award from the Sports Field Management Association in 2009, said the Cleveland grounds crew knew Perry’s preferences from his years pitching there. So, after he joined other teams, they leveraged that knowledge to tweak the star.

Perry loved to relax in the dugout hours before he pitched, and once, before a game in Cleveland, he sat in the visitors’ dugout early in the afternoon, taking in the view. Soon enough, the Cleveland grounds crew rolled out the mowers, driving them back and forth across the infield right in front of a grumbling Perry.

“What he didn’t know is that we had turned off the blades,” said Burns, now a specialist with DuraEdge Products, a manufacturer of specialized infield dirt for more than half the 30 clubs.

Perry had some tricks of his own. If the opposing pitcher was doing well, Perry would wait until his turn on the mound and then dig away at the other pitcher’s landing spot, covering it up or creating a ridge, Burns said. Few pitchers worry about such tactics now.

“There are little nuances here and there,” said Nicole Sherry, the head groundskeeper for the Baltimore Orioles. “But as far as tricking the field to manipulate it for your team, that’s in the past. Everything is done for safety and playability of the game. The aesthetics of the field comes last.”

High-Tech Grass and Remote Lasers

Today’s grass height is usually determined by the requirements and health of the plant, depending on whether it is Kentucky bluegrass or Bermuda. The bluegrass at Camden Yards grows about the length of a fingernail overnight, Sherry said, so they cut it back every day to about 1¼ inches.

Sherry, who has a degree in agriculture from the University of Delaware and is a member of the Sports Field Management Association, has been the head groundskeeper at Camden Yards since 2006 and started working on the crew in 2001. During that time she has seen remarkable advancements in growing methods. Fields are now sodded with genetically designed grass and nurtured with improved fertilizers that zero in on problem areas while crews employ sensors to measure moisture and other variables.

All of it, combined with years of gained expertise and an understanding of the climate surrounding each park, helps produce those luscious carpets of vivid green grass seen all across baseball.

But Baltimore’s grass, a shining gem in the middle of Charm City, has one persistent pollutant: the sunflower seeds and gum spit out in volume by players and umpires during games. In some parks, waste like that is vacuumed up after games. In Baltimore, Sherry’s crew picks it up — pounds of it — by hand, More than a dozen crew members with rubber gloves scour the fields for over an hour after every game.

“If we left every sunflower seed out there, the field would look like it was covered in snow,” she said as she flicked at the grass behind first base, revealing some rogue shells expelled by an umpire the night before.

There are other culprits, too. Many groundskeepers chafe at a recent trend in which visiting coaches wander the outfield grass with range finders before games. The devices are used to help position the outfielders, and the coaches sometimes scuff out marks in the grass with their heels, blemishing the near-perfect sod.

But it isn’t just the grass. Grounds crews are equally meticulous with the infield dirt. Sherry said infields must be watered, almost to the point of saturation, before games and covered with just the right amount of top dressing. She also noted that they lose moisture quickly, especially during day games, when the clay fries in the summer sun.

“The ball is coming off those bats way faster than it did in 2001,” she said. “The infielders want the dirt muddy in the first inning, so if the ball is coming off the bat at 100 miles per hour, they feel more at ease in the field.”

The amount of water poured on the dirt areas, especially in front of home plate, is one of the tools that grounds crews can still use to craft a favorable playing surface. Soaking the area in front of the plate theoretically slows the pace of the ball on its first bounce. Years ago, some crews watered the area into a swampy bayou. But most of the differences that exist today are negligible by comparison.

“A lot of fields have little differences, and sometimes you don’t know until you see the ball go there,” said Anthony Santander, an Orioles outfielder. “But the home teams, they know.”

Sherry said pitching mounds required the most attention on any field, and get the most scrutiny. M.L.B. measures every mound in baseball, including in the bullpens, using laser technology called lidar, an acronym for light detection and ranging. Before the season, every field is mapped with lasers, and the information is used for a variety of purposes, including pitch tracking, home run distances and physical dimensions of the park.

From field offices in Colorado, M.L.B. can detect if the mound is a half-inch higher or lower than the 10 inches prescribed by the rule book.

“We want teams to have confidence, when they go on the road, the game environment has been evaluated,” Clay Nunnally, a baseball scientist at M.L.B., said. “What we found from using pretty sophisticated measurements is that the groundskeepers are incredibly good at laying out the field.”

More Events, More Stress

The rules on positioning, combined with the pitch clock speeding things up, have been good for the fields.

“Shorter games means less wear and tear on the field,” Cook said, “so from an operation standpoint, it’s a plus.”

But some of that benefit is countered by teams seeking more profits by using the fields on off days to host concerts, monster truck exhibitions or soccer games. (The M.L.S. team New York City F.C. is splitting its home games between Yankee Stadium and Citi Field this year.)

All of it means a lot more work for the grounds crews. A normal soccer game entails players sliding, lunging and kicking out divots; the mound has to be taken down and reassembled; and grass must be placed over dirt areas. For concerts, boards are set atop the grass for hours at a time.

One day it’s a Bad Bunny concert at Yankee Stadium, the next day it’s a bad hop.

And groundskeepers shudder at the thought of motocross.

“The field used to be hallowed ground,” Burns said. “Now it’s another commodity for sale, another revenue stream.”

But groundskeepers are learning how to accommodate multiple events, and innovations in field maintenance help to counter the stresses.

In San Francisco, Elliott is at the forefront of baseball’s agricultural tech boom. In addition to the drone, he uses robotic mowers and Artificial Athlete, a device developed by Raw Stadia, a British company specializing in turf management for English soccer teams. Elliott places the portable tool in 15 spots on the field, where it releases a Clegg impact hammer to test various properties of the surfaces, like density, shock absorption, spring rate and recovery time. The data can be combined with information on individual athletes to enhance performance and health.

Elliott also brews his own microbial slurries, which are injected into the irrigation system and then sprayed on the grass. The specific microscopic organisms, including nitrogen fixers, enhance plant growth and health.

“It’s preventative medicine,” he said, “like eating vegetables.”

Elliott shares all his information with colleagues around the league, and once a year they gather to share notes and compare best practices. Where there was once gamesmanship, there is now communal knowledge that helps ensure every M.L.B. field is a suitable stage for the games played on them.

“The players are the best athletes in the world,” Sherry said, “and we are all the best groundskeepers in the world.”