The steroid era saw an explosion of home runs and scoring in the major leagues, and some parks amplified these effects even more. Coors Field in 2000 was the pinnacle of extreme scoring: 6.25 runs were scored per game (in 2016, 4.48 runs were scored per game across all parks). However, 2000’s Coors Field was not the most extreme home run park in MLB history; that title belongs to one of the oddest parks of all time, the Polo Grounds.

The Polo Grounds that is remembered by us today was not the first Polo Grounds but the fourth. The first existed just north of Central Park in Manhattan, and was the only one where polo was actually played. The field was the home to both the Giants and the Metropolitans, who often played simultaneous games with separate diamonds on either end of the field. A portable fence was used to cut the playing field in half and balls that went over were home runs, but balls that rolled under were still considered in play. The stadium was used for baseball until 1889, when the city of New York proceeded with plans to extend 111th Street, cutting through the field and placing a traffic circle in its center.

The next home for Major League Baseball in New York would be located just off the Harlem River near 155th Street in Manhattan, the area where the Polo Grounds would stay until its final demolition. This field maintained the shape of a polo field, even though polo was never played there. It also included a steep embankment running to right field, and during rainy games fielders were often unable to climb the steep slope. In July of 1889, the New York Giants moved into this new home. During the Giants’ time there, Brotherhood Park was built next door for the New York Players’ League. Two years after its formation, the Players’ League was dissolved, and the Giants moved next door into the nicer Brotherhood Park, which was renamed the Polo Grounds, with the Old Polo Grounds becoming Manhattan Field.

The third Polo Grounds was where the field gained its distinctive horseshoe shape that the name became synonymous with, and where the Giants won their first of the five World Series titles they would win in New York. A chance at a sixth was taken from the Giants due to the strange ending of the “Merkle’s Boner” game in 1908, also at the third Polo Grounds. Then in April of 1911, a fire that started in the grandstands engulfed the stadium and burned all but the bleachers and the offices to the ground.

However, reconstruction moved quickly, and only 11 weeks after the fire, a new stadium stood ready for baseball. The wooden construction of the last field was replaced with new concrete and steel construction to ensure the stadium’s longevity. The Giants’ owner John T. Brush tried to name the stadium Brush Stadium after himself, but fans and reporters kept the name Polo Grounds alive.

The Giants spent the remainder of their time in New York in this fourth and final Polo Grounds, where they would win four World Series. From 1913 to 1922 the Giants shared their new stadium with the American League’s New York Yankees. The Polo Grounds was were Babe Ruth shattered his own single season home run record of 29 with 54 in 1920, and hit 59 the following year. In 1921 and 1922, the Yankees and Giants met in the World Series, and every game of both series was played at the Polo Grounds. The Yankees moved into their own stadium in 1923, but the Giants remained. In 1954 the Giants brought the Polo Grounds its final World Series, and in the opening game Willie Mays made his famous catch.

The Giants remained in New York and in the Polo Grounds until 1958, when they became the San Francisco Giants. When the New York Mets joined the National League in 1962 they played in the Polo Grounds while Shea Stadium was finishing construction. The Polo Grounds saw its last major league game on September 18, 1963, and its last baseball game when it hosted a Latin All-Star game that October. On April 10th, 1964 the Polo Grounds were torn down. The Giants had moved to San Francisco, the Yankees to Yankee Stadium, and the Mets to Shea Stadium. But what if the Polo Grounds had stayed around through the steroid era? How would one of baseball’s oddest parks play in one of its most extreme eras?

The Polo Grounds measured 279 down the left field line, and 258 down the right field line.  No active major league ballpark in less than 300 for either, with Fenway’s 302 foot left field line being the current shortest. In contrast, the distances of 447 to left center, 440 to right center and 483 to center are all the deepest in major league history. The stadium led to short flies down the lines turning into home runs and deep drives to center field turning into outs. However, for all of the Polo Grounds’ anomalies the park produced a league average run environment in the New York Giants final years, according to Fangraphs. The extremely large outfield was counteracted by the massive amount of home runs that were hit in the park.

To see how the home run factors of the Polo Grounds stack up to modern stadiums, we can calculate the park factor for the Polo Grounds home runs. Using Brandon Heipp’s and Fangraphs’ formula for 5-year park factors I calculated a home run factor for the Polo Grounds from 1953-1957. Below is the data for home runs hit and allowed by the New York Giants from 1953-1957:

During this span the Giants played 386 games at home and 385 games on the road, for a HR/G rate of 2.40 and 1.59 respectively. For the calculation of the park factor I used HR/G rather than HR/PA, because a player’s ability to hit home runs in the Polo Grounds would also be affected by the amount of PA that the player gets in that park. Using Fangraph’s formula and the data above, I calculated the HR park factor for the Polo Grounds to be 1.42. According to Fangraphs the home run factor for 2000 Coors Field was 1.26.

But how does this factor translate to the largest home run hitters of the steroid era? In 2001 Barry Bonds hit 37 home runs at home, in a park with the lowest HR factor in the league that year, 0.89. Using the factor for the 1953-1957 Polo Grounds, he would have hit 59 at home, raising his number on the season to 95. 1998 Sammy Sosa would have hit 79,  and Mark McGwire would have topped 84. The home run factor at the Polo Grounds could have become even more extreme if it had survived until the steroid era, as hitters became stronger and balls flew further. However this method isn’t perfect, and these estimates are only that, estimates.

While many in today’s game both enjoy and lament the extremes of Coors Field, the Polo Grounds was even more extreme to play in. The ways that it was can’t be immediately seen by looking at the number of runs per game there, but can be seen in the types of plays that the Polo Grounds encouraged, or in just one look at a photo of this odd field.