If Yankee Stadium is the house that Ruth built, then an offseason ice rink in an Eagan park is the house that Truck built.

That's where Pat "Truck" Moriarty created a miniature baseball diamond, planting bases inside the fenced-in area used in the winter for broomball. He recruited guys who barely knew one another and gave them a kids' toy: a skinny, yellow plastic bat and a hollow plastic ball with holes in it. Then he told them to play ball.

Thus began what organizers say is now the biggest adult Wiffle ball league in the country.

Wiffle ball, in case you didn't know, is a plaything invented in 1953 by a guy named David Mullany, a retired semipro baseball pitcher from Connecticut. To make it easier for his 12-year-old son to throw a curveball, Mullany cut oblong holes into one side of a hollow plastic sphere and created a ball so swerve-prone that even little kids could hurl some nasty junk.

When the lightweight ball was hit with an equally lightweight bat, the ball wouldn't fly far and it wasn't heavy enough to break a window, making it perfect for youngsters to knock around the backyard, often in a game with improvised rules.

Wiffle balls (named after "whiff," a slang term for a strikeout) became the Mullany family business, selling by the millions and getting inducted into the National Toy Hall of Fame in 2017.

But some kids who grew up playing Wiffle ball never outgrew it.

Moriarty, who's from Massachusetts, played baseball from Little League to college. But for much of that time, he also played in a Wiffle ball league that started in the New England state in the late 1980s.

When he moved to Minnesota in 2003 at the age of 28, he couldn't find any organized Wiffle ball teams, so he set out to start his own league.

"I wanted to re-create what I had in Mass," he said. "I wanted to re-create the camaraderie."

According to a mini YouTube documentary on the origins of the Home Run League (hrltwincities.com), Moriarty posted messages on a Wiffle ball website in early 2004, which led to an article in the St. Paul Pioneer Press and an appearance on KFAN Radio. By that spring, he had attracted interest from about 40 guys, enough to form eight teams.

He also found a venue near where he lived, an ice rink in Sky Hill Park in Eagan, that the league used once they got park officials' OK.

"There was a lot of explaining because they didn't quite get the sport," Moriarty said.

The league was a hit from the start, quickly expanding to 16 teams and a second location in Hopkins. Now there are 22 teams with about 160 players, many of whom played baseball in high school and college. There's even one former Major Leaguer, a player on the Kardinals team, John "Boom" Gaub, a South St. Paul guy who played for the Gophers and pitched briefly for the Chicago Cubs in 2011.

Richard Chin
Video (01:28) Adult wiffle ball league is game on

Most players are men, but there are a handful of women in the organization. Players range in age from 20-year-old John "Epstein" Cronin to 68-year-old Steve "Palpatine" Payne, who's reliving his American Legion Baseball pitching days.

"It's fun, but it's still a challenge," Payne said. "I work as hard pitching at Wiffle ball as I was pitching American Legion."

In case you're wondering, the league requires every player to have a nickname.

"We're not just going to call you Steve," Moriarty said.

Rules and etiquette

Under Home Run League rules, the bases are only 45 feet apart, half the distance of a regulation baseball diamond. That's why it's possible to squeeze two diamonds inside the ice rink.

Games last six innings, and teams play doubleheaders on Monday and Thursday nights from April until August. It takes three strikes for an out, but five balls for a walk. The umpire is a 30-by-20-inch piece of plywood standing a foot off the ground behind home plate. If the pitcher can hit that target, it's a strike.

Teams can have as many as eight batters in the lineup, but, aside from the pitcher, there are only two fielders. If a fielder can grab a grounder before the baserunner gets to first, that's an out. You can also get an out by "pegging" — throwing and hitting a player when he's running between the bases.

Fielders play barehanded and all the bats have to be the classic, banana-yellow Wiffle brand bats that you can buy at Walmart for $3.91.

"We're kind of Wiffle purists," Moriarty said.

To give the batters a chance in this pitching-dominated game, there's a speed limit of 60 miles per hour on pitches, enforced by a radar gun if necessary. (Some league pitchers can throw heaters that hit 80 miles per hour, pretty fast plastic when the pitching mound is only 42 feet from home plate.)

Some unwritten rules of baseball etiquette are disregarded in Wiffle ball.

"We must stand and watch our home run until it lands and then start running," said Luke "Mippey5" Thompson, a player from Fridley. "When you hit a dong, the bigger the bat flip the better."

The Kardinals team ("K because we strike out a lot") throws birdseed to celebrate a homer.

In other words, the players at the Wiffle rink want to compete, but they also want to have a good time.

"I think it's more fun," said Nick "Sanchez" Consoer, a former baseball and softball player who holds the league's career home run record with 485 homers and counting.

"I was asking myself, 'What's another way to meet women and get famous?' and this seemed to be a natural choice," said Thompson. But he admits that when he tells people he plays Wiffle ball, they ask, "Aren't you an adult?"

Even worse: "Most people unmatch me on Tinder when I open with 'I'm on the No. 1 ranked Wiffle ball team in the nation,' " he said.

Balancing fun, competition

One thing the league does take seriously is statistics. The league has exhaustive records for each player and team back to 2004.

"I can look at my career OPS [on-base plus slugging statistic] against one particular pitcher," said Zachary "Dr. Seuss" Eustis, 35, from Little Canada.

The league also has an All-Star game, awards ceremonies, playoffs and a seven-game championship series at the end of the season. Big games are videotaped or livestreamed. There are online player profiles, articles and custom Wiffle-themed team logos. One championship team even printed baseball cards for its members.

Each year the Home Run League also sends a squad of its best players to a National Wiffle League Association championship in Morenci, Mich. And since 2005, Moriarty has held a benefit tournament open to anyone called Wifflin' for Wishes (­wifflinforwishes.com), which has raised more than $50,000 for Make-A-Wish Minnesota.

Players say the balance between fun and competition is reflection of Moriarty's guiding vision.

"Truck is such a charismatic and outgoing guy," Eustis said. "Truck's personality has really defined the league."

"He's the godfather," Thompson said. "He's the guy who started it all."

Moriarty, who is now 44 and lives in Cottage Grove, said he'll keep playing as long as his body holds up. But he maintains that this is his last — or next to last season — as league commissioner.

He's hoping to groom a younger generation to take over.

"I kind of feel like a proud papa in a lot of ways," he said.