RENSSELAER — Each time Matt Malette stepped across the sodden field, his brown leather Oxford shoes made a slurping sound as he picked his steps across a muddy expanse speckled with Canada geese droppings.

Sandwiched between the Hudson River and Broadway, near the Amtrak train station, this forlorn patch of low-lying real estate hardly looks like a spot where major league baseball history was made more than a century ago. It sits in the shadow of a Dunn Memorial Bridge ramp.

There is no bronze plaque or anything to designate that herein lies the spot where Roger Connor became the first player to hit a grand slam in Major League Baseball history on Sept. 10, 1881, for the National League Troy Trojans in a game against the Worcester Ruby Legs.

"Connor's grand slam was the first in MLB history," John Thorn, official historian of Major League Baseball, confirmed in an email.

The grand slam is described in the definitive Society for American Baseball Research, but it erroneously listed Albany as the location.

"It took almost three years of sleuthing to get this all sorted out," said Malette, who maintains the popular local history Twitter feed @AlbanyArchives and produces history segments for Spectrum News, where he works as a graphic designer.

With the Major League Baseball seasons getting off to an early start when the Seattle Mariners face the Oakland A's Wednesday in Japan, Malette was in the mood to share how he uncovered the little-known nugget of MLB history.

The biggest obstacle for Malette was pinpointing the grand slam's location, which was cited as Riverside Park in Albany.

But Albany's Riverside Park, a small pocket park along the Hudson in downtown, opened in 1903, 21 years after the grand slam. "You've got the wrong Riverside Park," Albany historian Tony Opalka told Malette.

Malette found out there was a Riverside Park in Rensselaer, but Rensselaer did not get chartered as a city until 1897, 16 years after the grand slam.

Malette, who hosts local history trivia contests at area bars, dug deeper into the Riverside Park mystery. In 1881, the area that became the city of Rensselaer was the village of Greenbush and included two hamlets, Bath and East Albany. "Someone got it wrong 138 years ago by labeling the grand slam in Albany instead of East Albany," Malette said.

Riverside Park – a popular late-19th century swimming spot notable for allowing bathing in the nude – was situated on privately-owned Bonacker Island. The Bonackers were a prominent Rensselaer family who cut ice along the Hudson and stored it in an ice house on the island. The structure burned down in the early 1930s. The island was later covered with fill during construction of the Dunn Memorial Bridge, completed in 1969.

Malette uncovered a newspaper clipping from August, 1878 that mentioned a baseball field in Riverside Park on Bonacker Island. By overlaying historic maps with satellite views, he determined that the ball field was roughly the size of Yankee Stadium.

There was another aspect that stumped Malette. The Troy Trojans, a major league team in the National League, played four seasons from 1879 to 1882. Their home games were held on baseball diamonds in Troy or Watervliet. Why, then, did the grand slam occur at Riverside Park on Bonacker Island?

"I went to the newspaper weather reports and it rained heavily the day before, so their regular fields must have been unplayable," Malette said.

The Sept. 10, 1881 game – a meaningless contest late in the season between two teams at the bottom of the standings – was moved to Riverside Park as an alternate site.

What's even more remarkable is that the Troy Trojans were down three runs to the Worcester Ruby Legs in the bottom of the ninth inning. The bases were loaded with two outs when Connor, a 24-year-old left-handed power hitter at 6-foot-3 and 220 pounds, came to the plate. Connor's mighty blow was also the first "ultimate" grand slam in major league history and it propelled Troy to victory, 8-7. "It was a terrific drive to right," the Worcester Daily Spy reported. Only about 100 fans saw Connors' feat as the two teams meet for the 12th and final time in the 1881 season in a game marred by numerous errors.

Worcester's left-hander Lee Richmond was the pitcher who gave up Connors' ultimate grand slam and he, too, earned a place in the annals of baseball.

"I commend Matt for his dogged research," said Guilderland Public Library director Tim Wiles, former director of research for the Baseball Hall of Fame in Cooperstown. "Not many people know a lot about 19th-century baseball and the so-called dead ball era."

Wiles, who spent 20 years at the Baseball Hall of Fame, noted that a small cadre of 19th-century baseball historians hold an annual conference in Cooperstown in April. "Even among the geekiest baseball fans, they are a very specialized group," Wiles said.

There is a post-script. Connor's ultimate grand slam walk-off was not repeated until Babe Ruth accomplished the feat on September 24, 1925. Connor had a lifetime total of 138 home runs, which earned him a place in the Hall of Fame.

"Home runs were actually frowned upon in that era because the emphasis was on strategy and moving players from base to base," Wiles said. "Babe Ruth eventually popularized home runs."

The baseball field where Connors made history with his grand slam later housed a Chrysler dealer, Airway Motors, from 1944 to 1960 when it moved to Central Avenue in Albany. William Bonacker died at 82 in 1965 and his obituary noted that he was the manager of a baseball team that played at Riverside Park on Bonacker Island at the turn-of-the-century.

Malette has talked with Rensselaer officials in a bid to have a commemorative plaque installed on the spot.

"It was exciting to finally pinpoint the spot of the first grand slam," Malette said. "I love solving a local history mystery."

Paul Grondahl is director of the New York State Writers Institute at the University at Albany and a former Times Union reporter. He can be reached at grondahlpaul@gmail.com